Transcutaneous analyte sensor systems and methods

ABSTRACT

Systems for applying a transcutaneous monitor to a person can include a telescoping assembly, a sensor, and a base with adhesive to couple the sensor to skin. The sensor can be located within the telescoping assembly while the base protrudes from a distal end of the system. The system can be configured to couple the sensor to the base by compressing the telescoping assembly.

INCORPORATION BY REFERENCE TO RELATED APPLICATIONS

Any and all priority claims identified in the Application Data Sheet, orany correction thereto, are hereby incorporated by reference under 37CFR 1.57. This application is a continuation of U.S. application Ser.No. 15/387,088, filed Dec. 21, 2016, which, in turn, claims the benefitof U.S. Provisional Application No. 62/272,983, filed Dec. 30, 2015 andU.S. Provisional Application No. 62/412,100, filed Oct. 24, 2016. Eachof the aforementioned applications is incorporated by reference hereinin its entirety, and each is hereby expressly made a part of thisspecification.

FIELD

Various embodiments disclosed herein relate to measuring an analyte in aperson. Certain embodiments relate to systems and methods for applying atranscutaneous analyte measurement system to a person.

BACKGROUND

Diabetes mellitus is a disorder in which the pancreas cannot createsufficient insulin (Type I or insulin dependent) and/or in which insulinis not effective (Type 2 or non-insulin dependent). In the diabeticstate, the victim suffers from high blood sugar, which can cause anarray of physiological derangements associated with the deterioration ofsmall blood vessels, for example, kidney failure, skin ulcers, orbleeding into the vitreous of the eye. A hypoglycemic reaction (lowblood sugar) can be induced by an inadvertent overdose of insulin, orafter a normal dose of insulin or glucose-lowering agent accompanied byextraordinary exercise or insufficient food intake.

Conventionally, a person with diabetes carries a self-monitoring bloodglucose monitor, which typically requires uncomfortable finger prickingmethods. Due to the lack of comfort and convenience, a person withdiabetes normally only measures his or her glucose levels two to fourtimes per day. Unfortunately, such time intervals are so far spreadapart that the person with diabetes likely finds out too late of ahyperglycemic or hypoglycemic condition, sometimes incurring dangerousside effects. Glucose levels may be alternatively monitored continuouslyby a sensor system including an on-skin sensor assembly. The sensorsystem may have a wireless transmitter which transmits measurement datato a receiver which can process and display information based on themeasurements.

The process of applying the sensor to the person is important for such asystem to be effective and user friendly. The application process canresult in the sensor assembly being attached to the person in a statewhere it is capable of sensing glucose level information, communicatingthe glucose level information to the transmitter, and transmitting theglucose level information to the receiver.

The analyte sensor can be placed into subcutaneous tissue. A user canactuate an applicator to insert the analyte sensor into its functionallocation. This transcutaneous insertion can lead to incomplete sensorinsertion, improper sensor insertion, exposed needles, or unnecessarypain. Thus, there is a need for a system that more reliably enablestranscutaneous sensor insertion while being easy to use and relativelypain-free.

SUMMARY

Various systems and methods described herein enable reliable, simple,and pain-minimizing transcutaneous insertion of analyte sensors. Someembodiments are a system for applying an on-skin sensor assembly to skinof a host. Systems can comprise a telescoping assembly having a firstportion configured to move distally relative to a second portion from aproximal starting position to a distal position along a path; a sensormodule coupled to the first portion, the sensor module including asensor, electrical contacts, and a seal; and/or a base coupled to thesecond portion such that the base protrudes from a distal end of thesystem. The base can comprise an adhesive configured to couple thesensor module to the skin. The moving of the first portion to the distalposition can couple the sensor module to the base. The sensor can be ananalyte sensor; a glucose sensor; any sensor described herein orincorporated by reference; and/or any other suitable sensor.

In some embodiments (i.e., optional and independently combinable withany of the aspects and embodiments identified herein), the sensor modulecan include a sensor module housing. The sensor module housing caninclude a first flex arm.

In some embodiments (i.e., optional and independently combinable withany of the aspects and embodiments identified herein), the sensor can belocated within the second portion while the base protrudes from thedistal end of the system such that the system is configured to couplethe sensor to the base via moving the first portion distally relative tothe second portion.

In several embodiments (i.e., optional and independently combinable withany of the aspects and embodiments identified herein), the sensor can becoupled to the sensor module while the first portion is located in theproximal starting position.

In some embodiments, a needle is coupled to the first portion (of thetelescoping assembly) such that the sensor and the needle move distallyrelative to the base and relative to the second portion. The system cancomprise a needle release mechanism configured to retract the needleproximally.

In several embodiments, the base comprises a distal protrusion having afirst hole. The distal protrusion can be configured to reduce aresistance of the skin to piercing. The sensor can pass through thefirst hole of the distal protrusion.

In some embodiments, a needle having a slot passes through the firsthole of the distal protrusion. A portion of the sensor can be located inthe slot such that the needle is configured to move distally relative tothe base without dislodging the portion of the sensor from the slot.

In several embodiments, the distal protrusion is convex such that thedistal protrusion is configured to tension the skin while the firstportion moves distally relative to the second portion to prepare theskin for piercing. The distal protrusion can be shaped like a dome.

In some embodiments, the adhesive comprises a second hole. The distalprotrusion can be located at least partially within the second hole suchthat the distal protrusion can tension at least a portion of the skinbeneath the second hole.

In several embodiments, the adhesive covers at least a majority of thedistal protrusion. The adhesive can cover at zero percent, at least 30percent, at least 70 percent, and/or less than 80 percent of the distalprotrusion. The distal protrusion can protrude at least 0.5 millimeters,less than 3 millimeters, and/or less than 5 millimeters.

In some embodiments, a sensor module is coupled to the first portion andis located at least 3 millimeters and/or at least 5 millimeters from thebase while the first portion is in the proximal starting position. Thesystem can be configured such that moving the first portion to thedistal position couples the sensor module to the base.

In several embodiments, the sensor is already coupled to the sensormodule while the first portion is located in the proximal startingposition. For example, the sensor can be coupled to the sensor module atthe factory (e.g., prior to the user opening a sterile barrier). Thesensor can be located within the second portion while the base protrudesfrom the distal end of the system.

In some embodiments, the sensor is coupled to a sensor module. During afirst portion of the path, the sensor module can be immobile relative tothe first portion, and the base can be immobile relative to the secondportion. During a second portion of the path, the system can beconfigured to move the first portion distally relative to the secondportion to move the sensor module towards the base, couple the sensormodule to the base, and/or enable the coupled sensor module and the baseto detach from the telescoping assembly.

In several embodiments, a sensor module is coupled to the sensor. Thesystem comprises a vertical central axis oriented from a proximal end tothe distal end of the system. The sensor module can comprise a firstflex arm that is oriented horizontally and is coupled to the base. Thefirst flex arm can extend from an outer perimeter of the sensor module.

In some embodiments, the base comprises a first proximal protrusioncoupled to the first flex arm to couple the sensor module to the base. Afirst horizontal locking protrusion can be coupled to an end portion ofthe first flexible arm. A second horizontal locking protrusion can becoupled to the first proximal protrusion of the base. The firsthorizontal locking protrusion can be located distally under the secondhorizontal locking protrusion to secure the sensor module to the base.The system can be configured such that moving the first portion of thetelescoping assembly to the distal position causes the first flex arm tobend to enable the first horizontal locking protrusion to move distallyrelative to the second horizontal locking protrusion.

In several embodiments, the base comprises a second proximal protrusioncoupled to a second flex arm of the sensor module. The first flex armcan be located on an opposite side of the sensor module relative to thesecond flex arm.

In some embodiments, a sensor module is coupled to the sensor. Thesystem can comprise a vertical central axis oriented from a proximal endto the distal end of the system. The base can comprise a first flex armthat is oriented horizontally and is coupled to the sensor module. Thesensor module can comprise a first distal protrusion coupled to thefirst flex arm to couple the sensor module to the base.

In several embodiments, a first horizontal locking protrusion is coupledto an end portion of the first flexible arm, a second horizontal lockingprotrusion is coupled to the first distal protrusion of the sensormodule, and the second horizontal locking protrusion is located distallyunder the first horizontal locking protrusion to secure the sensormodule to the base. The system can be configured such that moving thefirst portion of the telescoping assembly to the distal position causesthe first flex arm to bend to enable the second horizontal lockingprotrusion to move distally relative to the first horizontal lockingprotrusion.

In some embodiments, the sensor module comprises a second distalprotrusion coupled to a second flex arm of the base. The first distalprotrusion can be located on an opposite side of the sensor modulerelative to the second distal protrusion.

In several embodiments, a sensor module is coupled to the sensor. Thefirst portion can comprise a first flex arm and a second flex arm thatprotrude distally and latch onto the sensor module to releasably securethe sensor module to the first portion while the first portion is in theproximal starting position. The sensor module can be located remotelyfrom the base while the first portion is in the proximal startingposition (e.g., such that the sensor module does not touch the base).

In some embodiments, the sensor module is located within the secondportion while the base protrudes from the distal end of the system suchthat the system is configured to couple the sensor module to the basevia moving the first portion distally relative to the second portion.

In several embodiments, the system comprises a vertical central axisoriented from a proximal end to the distal end of the system. The firstand second flex arms of the first portion can secure the sensor moduleto the first portion such that the sensor module is releasably coupledto the first portion with a first vertical holding strength. The sensormodule can comprise a third flex arm coupled with a first proximalprotrusion of the base such that the sensor module is coupled to thebase with a second vertical holding strength.

In some embodiments, the second vertical holding strength is greaterthan the first vertical holding strength such that continuing to pushthe first portion distally once the sensor module is coupled to the baseovercomes the first and second flex arms of the first portion to detachthe sensor module from the first portion. The third flex arm can extendfrom an outer perimeter of the sensor module.

In several embodiments, the base protrudes from the distal end of thesystem while the first portion of the telescoping assembly is located inthe proximal starting position and the sensor is located remotelyrelative to the base such that the system is configured to couple thesensor to the base via moving the first portion distally relative to thesecond portion. The base can comprise a first radial protrusionreleasably coupled with a first vertical holding strength to a secondradial protrusion of the second portion of the telescoping assembly.

In some embodiments, the first radial protrusion protrudes inward andthe second radial protrusion protrudes outward. The system can beconfigured such that moving the first portion to the distal positionmoves the second radial protrusion relative to the first radialprotrusion to detach the base from the telescoping assembly.

In several embodiments, the first portion of the telescoping assemblycomprises a first arm that protrudes distally, the second portion of thetelescoping assembly comprises a second flex arm that protrudesdistally, and the system is configured such that moving the firstportion from the proximal starting position to the distal position alongthe path causes the first arm to deflect the second flex arm and therebydetach the second flex arm from the base to enable the base to decouplefrom the telescoping assembly. When the first portion is in the proximalstarting position, the first arm of the first portion can be at leastpartially vertically aligned with the second flex arm of the secondportion to enable the first arm to deflect the second flex arm as thefirst portion is moved to the distal position.

In some embodiments, when the first portion is in the proximal startingposition, at least a section of the first arm is located directly overthe second flex arm to enable the first arm to deflect the second flexarm as the first portion is moved to the distal position.

In several embodiments, the second flex arm comprises a first horizontalprotrusion, and the base comprises a second horizontal protrusionlatched with the first horizontal protrusion to couple the base to thesecond portion of the telescoping assembly. The first arm of the firstportion can deflect the second flex arm of the second portion to unlatchthe base from the second portion of the telescoping assembly.

In some embodiments, the system is configured to couple the sensor tothe base at a first position, and the system is configured to detach thebase from the telescoping assembly at a second position that is distalrelative to the first position.

In several embodiments, a third flex arm couples the sensor to the baseat a first position, the second flex arm detaches from the base at asecond position, and the second position is distal relative to the firstposition such that the system is configured to secure the base to thetelescoping assembly until after the sensor is secured to the base.

In some embodiments, the base protrudes from the distal end of thesystem while the first portion of the telescoping assembly is located inthe proximal starting position and the sensor is located remotelyrelative to the base. The system can further comprise a springconfigured to retract a needle. The needle can be configured tofacilitate inserting the sensor into the skin. When the first portion isin the proximal starting position, the spring can be in a firstcompressed state. The system can be configured such that moving thefirst portion distally from the proximal starting position furtherincreases a compression of the spring. The first compressed state placesthe first and second portions in tension.

In several embodiments, a system is configured to apply an on-skinsensor assembly to the skin of a host (i.e., a person). The system caninclude a telescoping assembly having a first portion configured to movedistally relative to a second portion from a proximal starting positionto a distal position along a path; a sensor coupled to the firstportion; and/or a latch configurable to impede a needle from movingproximally relative to the first portion. The sensor can be an analytesensor; a glucose sensor; any sensor described herein or incorporated byreference; and/or any other suitable sensor.

In some embodiments, the first portion is releasably secured in theproximal starting position by a securing mechanism that impedes movingthe first portion distally relative to the second portion. The systemcan be configured such that prior to reaching the distal position,moving the first portion distally relative to the second portionreleases the latch thereby causing the needle to retract proximally intothe system. The system can be configured such that moving the firstportion distally relative to the second portion (e.g., moving the firstportion to the distal position) releases the latch thereby causing theneedle to retract proximally into the system. The securing mechanism canbe an interference between the first portion and the second portion ofthe telescoping assembly.

In several embodiments, a first force profile is measured along thepath. The first force profile can comprise a first magnitude coincidingwith overcoming the securing mechanism; a third magnitude coincidingwith releasing the latch; and a second magnitude coinciding with anintermediate portion of the path that is distal relative to overcomingthe securing mechanism and proximal relative to releasing the latch.

In some embodiments, the second magnitude is less than the first andthird magnitudes such that the system is configured to promote needleacceleration during the intermediate portion of the path to enable asuitable needle speed (e.g., a sufficiently high needle speed) at a timethe needle first pierces the skin.

In several embodiments, the first magnitude is at least 100 percentgreater than the second magnitude. The first magnitude can be greaterthan the third magnitude such that the system is configured to impedeinitiating a sensor insertion cycle unless a user is applying enoughforce to release the latch. The first magnitude can be at least 50percent greater than the third magnitude.

In some embodiments, an intermediate portion of the path is distalrelative to overcoming the securing mechanism and proximal relative toreleasing the latch. The system can further comprise a second forceprofile coinciding with the intermediate portion of the path. A proximalmillimeter of the second force profile can comprise a lower averageforce than a distal millimeter of the second force profile in responseto compressing a spring configured to enable the system to retract theneedle into the telescoping assembly.

In several embodiments, a first force profile is measured along thepath. The first force profile can comprise a first average magnitudecoinciding with moving distally past a proximal half of the securingmechanism and a second average magnitude coinciding with moving distallypast a distal half of the securing mechanism. The first averagemagnitude can be greater than the second average magnitude such that thesystem is configured to impede initiating a sensor insertion cycleunless a user is applying enough force to complete the sensor insertioncycle (e.g., drive the needle and/or the sensor to the intendedinsertion depth).

In some embodiments, a first force peak (coinciding with moving distallypast the proximal half of the securing mechanism) is at least 25 percenthigher than the second average magnitude.

In several embodiments, a first force profile is measured along thepath. The first force profile can comprise a first magnitude coincidingwith overcoming the securing mechanism and a subsequent magnitudecoinciding with terminating the securing mechanism. The first magnitudecan comprise a proximal vector and the subsequent magnitude can comprisea distal vector.

In some embodiments, the securing mechanism can comprise a radiallyoutward protrusion extending from the first portion. The radiallyoutward protrusion can be located proximally relative to a proximal endof the second portion while the telescoping assembly is in the proximalstarting position. The radially outward protrusion can be configured tocause the second portion to deform elliptically to enable the firstportion to move distally relative to the second portion.

In several embodiments, the securing mechanism comprises a radiallyoutward protrusion of the first portion that interferes with a radiallyinward protrusion of the second portion such that the securing mechanismis configured to cause the second portion to deform elliptically toenable the first portion to move distally relative to the secondportion.

In some embodiments, the needle is retractably coupled to the firstportion by a needle holder configured to resist distal movement of thefirst portion relative to the second portion. The securing mechanism cancomprise a flexible arm of the second portion. The flexible arm can bereleasably coupled to the needle holder to releasably secure the firstportion to the second portion in the proximal starting position.

In several embodiments, the securing mechanism comprises a frangiblecoupling between the first portion and the second portion while thefirst portion is in the proximal starting position. The system can beconfigured such that moving the first portion to the distal positionbreaks the frangible coupling.

In some embodiments, the securing mechanism comprises a magnet thatreleasably couples the first portion to the second portion while thefirst portion is in the proximal starting position. The magnet can beattracted to a metal element coupled to the first portion or the secondportion of the telescoping assembly.

In several embodiments, an electric motor drives the first portiondistally relative to the second portion. The electric motor can beconfigured to move the needle in the skin.

In some embodiments, an on-skin sensor system is configured fortranscutaneous glucose monitoring of a host. The system can comprise asensor module housing, in which the sensor module housing can include afirst flex arm; a sensor having a first section configured forsubcutaneous sensing and a second section mechanically coupled to thesensor module housing; an electrical interconnect mechanically coupledto the sensor module housing and electrically coupled to the sensor;and/or a base coupled to the first flex arm of the sensor modulehousing. The base can have an adhesive configured to couple the base tothe skin of the host. The sensor can be an analyte sensor; a glucosesensor; any sensor described herein or incorporated by reference; and/orany other suitable sensor.

In several embodiments, the electrical interconnect comprises a spring.The spring can comprise a conical portion and/or a helical portion.

In some embodiments, the sensor module housing comprises at least twoproximal protrusions located around a perimeter of the spring. Theproximal protrusions can be configured to help orient the spring. Asegment of the sensor can be located between the proximal protrusions.

In several embodiments, the sensor module housing is mechanicallycoupled to a base having an adhesive configured to couple the base toskin of the host.

In some embodiments, the proximal protrusions orient the spring suchthat coupling an electronics unit to the base presses the spring againsta first electrical contact of the electronics unit and a secondelectrical contact of the sensor to electrically couple the sensor tothe electronics unit.

In several embodiments, the sensor module housing comprises a first flexarm that is oriented horizontally and is coupled to the base. The firstflex arm can extend from an outer perimeter of the sensor modulehousing. The base can comprise a first proximal protrusion coupled tothe first flex arm to couple the sensor module housing to the base.

In some embodiments, the electrical interconnect comprises a leafspring, which can include one metal layer or multiple metal layers. Theleaf spring can be a cantilever spring.

In some embodiments, the sensor module housing comprises a proximalprotrusion having a channel in which at least a portion of the secondsection of the sensor is located. The channel can position a first areaof the sensor such that the first area is electrically coupled to theleaf spring.

In some embodiments, the leaf spring arcs away from the first area andprotrudes proximally to electrically couple with an electronics unit. Atleast a portion of the leaf spring can form a “W” shape. At least aportion of the leaf spring forms a “C” shape.

In several embodiments, the leaf spring bends around the proximalprotrusion. The leaf spring can bend at least 120 degrees and/or atleast 160 degrees around the proximal protrusion. The leaf spring canprotrude proximally to electrically couple with an electronics unit.

In some embodiments, a seal is configured to impede fluid ingress to theleaf spring. The sensor module housing can be mechanically coupled to abase. The base can have an adhesive configured to couple the base toskin of the host.

In several embodiments, the leaf spring is oriented such that couplingan electronics unit to the base presses the leaf spring against a firstelectrical contact of the electronics unit and against a secondelectrical contact of the sensor to electrically couple the sensor tothe electronics unit. A proximal height of the seal can be greater thana proximal height of the leaf spring such that the electronics unitcontacts the seal prior to contacting the leaf spring.

In some embodiments, the sensor module housing comprises a first flexarm that is oriented horizontally and is coupled to the base. The firstflex arm can extend from an outer perimeter of the sensor modulehousing. The base can comprise a first proximal protrusion coupled tothe first flex arm to couple the sensor module housing to the base.

In several embodiments, the sensor module housing comprises a channel inwhich at least a portion of the second section of the sensor is located.A distal portion of the leaf spring can be located in the channel suchthat a proximal portion of the leaf spring protrudes proximally out thechannel. The sensor module housing can comprise a groove that intersectsthe channel. The leaf spring can comprise a tab located in the groove toimpede rotation of the leaf spring.

In some embodiments, the sensor module housing is mechanically coupledto a base that has an adhesive configured to couple the base to skin ofthe host. The sensor module housing can comprise a first flex arm thatis oriented horizontally and is coupled to the base. The first flex armcan extend from an outer perimeter of the sensor module housing. Thebase can comprises a first proximal protrusion coupled to the first flexarm to couple the sensor module housing to the base.

In several embodiments, electrical interconnects (such as springs orother types of interconnects) comprises a resistance of less than 100ohms and/or less than 5 ohms. Electrical interconnects can comprise acompression force of less than one pound over an active compressionrange.

In some embodiments, electrical interconnects may require a compressionforce of less than one pound to compress the spring 20 percent from arelaxed position, which is a substantially uncompressed position. Insome embodiments, electrical interconnects may require a compressionforce of less than one pound to compress the spring 25 percent from arelaxed position, which is a substantially uncompressed position. Insome embodiments, electrical interconnects may require a compressionforce of less than one pound to compress the spring 30 percent from arelaxed position, which is a substantially uncompressed position. Insome embodiments, electrical interconnects may require a compressionforce of less than one pound to compress the spring 50 percent from arelaxed position, which is a substantially uncompressed position.

In several embodiments, the spring is configured such that compressingthe spring 25 percent from a relaxed position requires a force of atleast 0.05 pounds and less than 0.5 pounds, and requires moving an endof the spring at least 0.1 millimeter and less than 1.1 millimeter.

In some embodiments, a system for applying an on-skin sensor assembly toa skin of a host comprises a telescoping assembly having a first portionconfigured to move distally relative to a second portion from a proximalstarting position to a distal position along a path; a sensor coupled tothe first portion; and a base comprising adhesive configured to couplethe sensor to the skin. The telescoping assembly can further comprise athird portion configured to move distally relative to the secondportion.

In some embodiments, a first spring is positioned between the thirdportion and the second portion such that moving the third portiondistally relative to the second portion compresses the first spring. Inthe proximal starting position of the telescoping assembly, the firstportion can be locked to the second portion. The system can beconfigured such that moving the third portion distally relative to thesecond portion unlocks the first portion from the second portion.

In several embodiments, a first proximal protrusion having a first hookpasses through a first hole in the second portion to lock the firstportion to the second portion. The third portion can comprise a firstdistal protrusion. The system can be configured such that moving thethird portion distally relative to the second portion engages a ramp tobend the first proximal protrusion to unlock the first portion from thesecond portion.

In some embodiments, the sensor is located within the second portionwhile the base protrudes from the distal end of the system such that thesystem is configured to couple the sensor to the base by moving thefirst portion distally relative to the second portion.

In several embodiments, a sensor module is coupled to a distal portionof the first portion such that moving the first portion to the distalposition couples the sensor module to the base. The sensor can becoupled to the sensor module while the first portion is located in theproximal starting position.

In some embodiments, the system is configured such that moving the thirdportion distally relative to the second portion unlocks the firstportion from the second portion and locks the third portion to thesecond portion.

In several embodiments, the system comprises a first protrusion thatcouples with a hole of at least one of the second portion and the thirdportion to lock the third portion to the second portion.

In some embodiments, the system comprises a second protrusion thatcouples with a hole of at least one of the first portion and the secondportion to lock the first portion to the second portion in response tomoving the first portion distally relative to the second portion.

In several embodiments, a first spring is positioned between the thirdportion and the second portion such that moving the third portiondistally relative to the second portion compresses the first spring andunlocks the first portion from the second portion, which enables thecompressed first spring to push the first portion distally relative tothe second portion, which pushes at least a portion of the sensor out ofthe distal end of the system and triggers a needle retraction mechanismto enable a second spring to retract a needle.

In some embodiments, a system for applying an on-skin assembly to a skinof a host is provided. Advantageously, the system includes a sensorinserter assembly having a needle assembly, a sensor module, a base, anactuation member, and a retraction member, the sensor inserter assemblyhaving an initial configuration in which at least the sensor module isdisposed in a proximal starting position, the sensor inserter assemblyfurther having a deployed configuration in which at least the sensormodule and the base are disposed at a distal applied position.Preferably, the actuation member is configured to, once activated, causethe needle assembly to move a proximal starting position to a distalinsertion position, and the retraction member is configured to, onceactivated, cause the needle assembly to move from the distal insertionposition to a proximal retracted position.

The sensor module may comprise a sensor and a plurality of electricalcontacts. In the initial configuration, the sensor can be electricallycoupled to at least one of the electrical contacts. Optionally, in theinitial configuration, the actuation member is in an unenergized state.In some embodiments, the actuation member can be configured to beenergized by a user before being activated. In alternative embodiments,in the initial configuration, the actuation member is in an energizedstate.

In several embodiments the actuation member can include a spring. In aninitial configuration, the spring can be in an unstressed state. Inalternative embodiments, in the initial configuration, the spring is ina compressed state.

In some embodiments, the sensor inserter assembly may include a firstportion and a second portion, the first portion being fixed, at least inan axial direction, with respect to the second portion at least when thesensor inserter assembly is in the initial configuration, the firstportion being movable in at least a distal direction with respect to thesecond portion after activation of the actuation member. The firstportion may be operatively coupled to the needle assembly so as tosecure the needle assembly in the proximal starting position beforeactivation of the actuation member and to urge the needle assemblytoward the distal insertion position after activation of the actuationmember.

In several embodiments, the retraction member is in an unenergized statewhen in the initial configuration. Advantageously, the retraction memberis configured to be energized by the movement of the needle assemblyfrom the proximal starting position to the distal insertion position. Inthe initial configuration, the retraction member may be in an energizedstate.

In still other embodiments, the retraction member comprises a spring.The spring may be integrally formed with the needle assembly. The springmay be operatively coupled to the needle assembly. In the initialconfiguration, the spring may be in an unstressed state. In otherembodiments, in the initial configuration, the spring is in compression.

In some aspects, in the second configuration, the spring is incompression. In still other embodiments, in the second configuration,the spring is in tension.

In some embodiments, the sensor inserter assembly can further include athird portion, the third portion being operatively coupled to the firstportion. The actuation member may be integrally formed with the thirdportion in certain embodiments. Optionally, the actuation member isoperatively coupled to the third portion.

In some embodiments, the sensor inserter assembly includes interengagingstructures configured to prevent movement of the first portion in thedistal direction relative to the second portion until the interengagingstructures are decoupled. Advantageously, the decoupling of theinterengaging structures may activate the actuation member. In otherembodiments, the interengaging structures may include a proximallyextending tab of the first portion and a receptacle of the secondportion configured to receive the proximally extending tab. Optionally,the sensor inserter assembly can include a decoupling member configuredto decouple the interengaging structures. The decoupling member may havea distally extending tab of the third portion.

In yet other embodiments, the sensor inserter assembly can includeinterengaging structures configured to prevent proximal movement of thethird portion with respect to the first portion. These interengagingstructures may include a distally-extending latch of the third portionand a ledge of the first portion configured to engage thedistally-extending latch.

In certain embodiments, the sensor inserter assembly can includeinterengaging structures configured to prevent proximal movement of theneedle assembly at least when the needle assembly is in the distalinsertion position. The interengaging structures can haveradially-extending release features of the needle assembly and an innersurface of the first portion configured to compress the releasefeatures. Optionally, the sensor inserter assembly includes a decouplingmember configured to disengage the interengaging structures of the firstportion and the needle assembly. The decoupling member may include aninner surface of the second portion configured to further compress therelease features. Advantageously, the system may further include atrigger member configured to activate the actuation member. The triggermember may be operatively coupled to the third portion. The triggermember may be integrally formed with the third portion. The triggermember may include a proximally-extending button. Alternatively, thetrigger member may include a radially-extending button. The triggermember may be configured to decouple the interengaging structure of thefirst portion and the third portion.

In some embodiments, the system may further include a releasable lockingmember configured to prevent activation of the actuation member untilthe locking member is released. The releasable locking member may beconfigured to prevent proximal movement of the third portion withrespect to the first portion until the locking member is released. Thereleasable locking member may include a proximally-extending tab of thefirst portion and a latch feature of the third portion configured toreceive the proximally-extending tab. Advantageously, the releasablelocking member is configured to prevent energizing of the sensorinserter assembly. In other aspects, the releasable locking member isconfigured to prevent energizing of the actuation member.

Embodiments may further include a system for applying an on-skincomponent to a skin of a host, the system may include a sensor inserterassembly having an on-skin component being movable in at least a distaldirection from a proximal position to a distal position, a firstsecuring feature configured to releasably secure the on-skin componentin the proximal position, a second securing feature configured to securethe on-skin component in the distal position, and a first resistanceconfigured to prevent movement of the on-skin component in a proximaldirection at least when the on-skin component is in the distal position.

The first resistance feature can be configured to prevent movement ofthe on-skin component in a proximal direction when the on-skin componentis secured in the distal position. In some embodiments, the firstsecuring feature is configured to releasably secure the on-skincomponent to a needle assembly. The on-skin component may have a sensormodule. The sensor module may include a sensor and a plurality ofelectrical contacts. Optionally, the sensor is electrically coupled toat least one of the electrical contacts, at least when the sensorinserter assembly is in the first configuration.

In some embodiments, the on-skin component comprises a base. The on-skincomponent may include a transmitter. The second securing feature can beconfigured to secure the on-skin component to a second on-skincomponent.

In other embodiments, the sensor inserter assembly includes at least onedistally-extending leg, and wherein the first securing feature comprisesan adhesive disposed on a distally-facing surface of the leg. The sensorinserter assembly may include at least one distally-extending member,and wherein the first securing feature comprises a surface of thedistally-extending member configured to frictionally engage with acorresponding structure of the on-skin component. The correspondingstructure of the on-skin component may include an elastomeric member.Optionally, the distally-extending member includes at least one leg ofthe sensor inserter assembly. The distally-extending member may includea needle.

In some embodiments of the system, the second securing feature includesan adhesive disposed on a distally-facing surface of the on-skincomponent. The second securing feature may have an elastomeric memberconfigured to receive the on-skin component.

In other embodiments, the first resistance feature includes adistally-facing surface of the sensor inserter assembly. The firstresistance feature may be distal to an adhesive disposed on adistally-facing surface of the on-skin component.

The system may further include a pusher configured to move the on-skincomponent from the proximal position to the distal position. Optionally,the system can further include a decoupling feature configured todecouple the pusher from the on-skin component at least after theon-skin component is in the distal position. The decoupling feature mayhave a frangible portion of the pusher. Optionally, the decouplingfeature comprises a frangible portion of the on-skin component.

The system may further comprise a sensor assembly configured to couplewith the on-skin component, wherein a third securing feature isconfigured to releasably secure the sensor assembly in a proximalposition, and wherein a fourth securing feature is configured to securethe sensor assembly to the on-skin component.

Any of the features of each embodiment is applicable to all aspects andembodiments identified herein. Moreover, any of the features of anembodiment is independently combinable, partly or wholly with otherembodiments described herein in any way, e.g., one, two, or three ormore embodiments may be combinable in whole or in part. Further, any ofthe features of an embodiment may be made optional to other aspects orembodiments. Any aspect or embodiment of a method can be performed by asystem or apparatus of another aspect or embodiment, and any aspect orembodiment of a system can be configured to perform a method of anotheraspect or embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages are described belowwith reference to the drawings, which are intended to illustrate, butnot to limit, the invention. In the drawings, like reference charactersdenote corresponding features consistently throughout similarembodiments.

FIG. 1 illustrates a schematic view of a continuous analyte sensorsystem, according to some embodiments.

FIG. 2 illustrates a perspective view of an applicator system, accordingto some embodiments.

FIG. 3 illustrates a cross-sectional side view of the system from FIG. 2, according to some embodiments.

FIG. 4 illustrates a perspective view of an on-skin sensor assembly,according to some embodiments.

FIGS. 5 and 6 illustrate perspective views of a transmitter coupled to abase via mechanical interlocks, according to some embodiments.

FIGS. 7-11 illustrate cross-sectional side views of the applicatorsystem from FIG. 3 , according to some embodiments.

FIG. 12A illustrates a cross-sectional side view of a portion of theapplicator system from FIG. 3 , according to some embodiments.

FIG. 12B illustrates a cross-sectional side view of a base that can beused with the applicator system shown in FIG. 3 , according to someembodiments.

FIG. 13 illustrates a perspective view of a portion of the adhesive fromFIG. 4 , according to some embodiments.

FIG. 14 illustrates a perspective view of a portion of the applicatorsystem from FIG. 3 , according to some embodiments.

FIGS. 15 and 16 illustrate perspective views of cross sections ofportions of the system shown in FIG. 7 , according to some embodiments.

FIG. 17 illustrates a cross-sectional view of the first portion of thetelescoping assembly from FIG. 7 , according to some embodiments.

FIGS. 18 and 19 illustrate perspective views of portions of theapplicator system from FIG. 7 , according to some embodiments.

FIGS. 20 and 21 illustrate perspective views of the needle after beingremoved from the telescoping assembly of FIG. 7 , according to someembodiments.

FIG. 22 illustrates a perspective view of a cover of the telescopingassembly of FIG. 7 , according to some embodiments.

FIG. 23 illustrates a schematic view of force profiles, according tosome embodiments.

FIG. 24 illustrates a cross-sectional side view of a portion of anapplicator system, according to some embodiments.

FIG. 25 illustrates a cross-sectional side view of a portion of asecuring mechanism, according to some embodiments.

FIG. 26 illustrates a top view of a ring, according to some embodiments.

FIG. 27 illustrates a perspective view of a securing mechanism,according to some embodiments.

FIG. 28 illustrates a cross-sectional perspective view of telescopingassembly with a motor, according to some embodiments.

FIGS. 29 and 30 illustrate cross-sectional side views of telescopingassemblies with a motor, according to some embodiments.

FIG. 31 illustrates a side view of a telescoping assembly that causesrotational movement, according to some embodiments.

FIG. 32 illustrates a cross-sectional perspective view of a telescopingassembly with a downward locking feature, according to some embodiments.

FIG. 33 illustrates a perspective view of an on-skin senor assembly justbefore the electronics unit is coupled to the base, according to someembodiments.

FIGS. 34 and 35 illustrate perspective views of sensor modules that havesprings, according to some embodiments.

FIG. 36 illustrates a cross-sectional perspective view of a portion of asensor module, according to some embodiments.

FIG. 37 illustrates a perspective view of a sensor module that hassprings, according to some embodiments.

FIG. 38 illustrates a cross-sectional perspective view of a portion of asensor module, according to some embodiments.

FIG. 39 illustrates a perspective view of a sensor module, according tosome embodiments.

FIG. 40 illustrates a cross-sectional perspective view of assembly thathas an offset, according to some embodiments.

FIG. 41 illustrates a side view of a sensor, according to someembodiments.

FIG. 42 illustrates a bottom view of a needle, according to someembodiments.

FIG. 43 illustrates a front view of a needle, according to someembodiments.

FIG. 44 illustrates a cross-sectional perspective view of an applicatorsystem, according to some embodiments.

FIG. 45 illustrates a cross-sectional perspective view of a portion ofan applicator system, according to some embodiments.

FIG. 46 illustrates a perspective view of a portion of an applicatorsystem, according to some embodiments.

FIG. 47 illustrates a perspective view of a sensor module, according tosome embodiments.

FIG. 48 illustrates a cross-sectional perspective view of an applicatorsystem, according to some embodiments.

FIG. 49 illustrates a cross-sectional perspective view of a proximalportion of a telescoping assembly, according to some embodiments.

FIG. 50 illustrates a perspective view of a distal portion of atelescoping assembly, according to some embodiments.

FIG. 51 illustrates a perspective view of a needle with adhesive,according to some embodiments.

FIG. 52 illustrates a perspective view of a needle that has two separatesides, according to some embodiments.

FIG. 53 illustrates a cross-sectional top view of the needle shown inFIG. 52 , according to some embodiments.

FIG. 54 illustrates a perspective view of a needle that has a ramp,according to some embodiments.

FIG. 55 illustrates a cross-sectional top view of four needles,according to some embodiments.

FIGS. 56-58 illustrate cross-sectional side views of a system that issimilar to the embodiment shown in FIG. 7 except that the system doesnot include a needle, according to some embodiments.

FIG. 59 illustrates a cross-sectional side view of a system that issimilar to the embodiment shown in FIG. 7 except for the startingposition and the movement of the base, according to some embodiments.

FIG. 60 illustrates a perspective view of a system having a cover,according to some embodiments.

FIGS. 61-63 illustrate cross-sectional perspectives views of a systemthat is similar to the embodiment shown in FIG. 7 except that thetelescoping assembly includes an extra portion, according to someembodiments.

FIG. 64 illustrates a cross-sectional side view of the system shown inFIGS. 61-63 , according to some embodiments.

FIG. 65 illustrates a perspective view of portions of a sensor module,according to some embodiments.

FIG. 66 illustrates a cross-sectional side view of the sensor moduleshown in FIG. 65 , according to some embodiments.

FIG. 67 illustrates a perspective view of portions of a sensor module,according to some embodiments.

FIG. 68 illustrates a top view of the sensor module shown in FIG. 67 ,according to some embodiments.

FIGS. 69 and 70 illustrate perspective views of an electronics unit justbefore the electronics unit is coupled to a base, according to someembodiments.

FIG. 71 illustrates a cross-sectional perspective view of an applicatorsystem, according to some embodiments, in a resting state.

FIG. 72 illustrates a cross-sectional perspective view of the applicatorsystem of FIG. 71 , with the actuation member energized.

FIG. 73 illustrates a rotated cross-sectional perspective view of theapplicator system of FIG. 72 .

FIG. 74 illustrates a cross-sectional perspective view of the applicatorsystem of FIG. 71 , with the actuation member activated and with theneedle assembly deployed in an insertion position.

FIG. 75 illustrates a cross-sectional perspective view of the applicatorsystem of FIG. 71 , with the on-skin component in a deployed positionand the needle assembly retracted.

FIG. 76 illustrates a cross-sectional side view of another applicatorsystem, according to some embodiments, in a resting state.

FIG. 77 illustrates a cross-sectional side view of the applicator systemof FIG. 76 , with the actuation member energized.

FIG. 78 illustrates a cross-sectional side view of the applicator systemof FIG. 76 , with the actuation member activated and with the needleassembly deployed in an insertion position.

FIG. 79 illustrates a cross-sectional side view of the applicator systemof FIG. 76 , with the on-skin component in a deployed position and theneedle assembly retracted.

FIG. 80 illustrates a cross-sectional side view of another applicatorsystem, according to some embodiments, in a resting state.

FIG. 81 illustrates a cross-sectional side view of the applicator systemof FIG. 80 , with the actuation member energized.

FIG. 82 illustrates a cross-sectional side view of the applicator systemof FIG. 80 , with the actuation member activated and with the needleassembly deployed in an insertion position.

FIG. 83 illustrates a cross-sectional side view of the applicator systemof FIG. 80 , with the on-skin component in a deployed position and theneedle assembly retracted.

FIG. 84 illustrates a perspective view of the applicator system of FIG.80 , with the first and third portions shown in cross section to betterillustrate certain portions of the system, and in a resting state.

FIG. 85 illustrates a perspective view of the applicator system of FIG.80 , with the first and third portions shown in cross section to betterillustrate certain portions of the system, and with the actuation memberenergized.

FIG. 86 illustrates a cross-sectional side view of another applicatorsystem, according to some embodiments, in a resting state in which theactuation member is already energized.

FIG. 87 illustrates a cross-sectional side view of the applicator systemof FIG. 86 , with the actuation member activated and with the needleassembly deployed in an insertion position.

FIG. 88 illustrates a cross-sectional side view of the applicator systemof FIG. 86 , with the on-skin component in a deployed position and theneedle assembly retracted.

FIG. 89 illustrates a cross-sectional side view of another applicatorsystem, according to some embodiments, in a resting state in which theactuation member is already energized.

FIG. 90 illustrates a cross-sectional side view of the applicator systemof FIG. 86 , with the actuation member activated and with the needleassembly deployed in an insertion position.

FIG. 91 illustrates a cross-sectional side view of the applicator systemof FIG. 86 , with the on-skin component in a deployed position and theneedle assembly retracted.

FIG. 92 illustrates a side view of another applicator system, accordingto some embodiments, with a top trigger member, in a resting state.

FIG. 93 illustrates a side view of the applicator system of FIG. 92 ,after being cocked but before being triggered.

FIG. 94 illustrates a cross-sectional perspective view of the applicatorsystem of FIG. 92 , in a resting state.

FIG. 95 illustrates a cross-sectional perspective view of the applicatorsystem of FIG. 92 while being cocked.

FIG. 96 illustrates a cross-sectional perspective view of the applicatorsystem of FIG. 92 , after being cocked but before being triggered.

FIG. 97 illustrates a cross-sectional side view of the applicator systemof FIG. 96 .

FIG. 98 illustrates a cross-sectional side view of the applicator systemof FIG. 92 , during triggering.

FIG. 99 illustrates a cross-sectional side view of the applicator systemof FIG. 92 , after being triggered and with the needle assembly deployedin an insertion position.

FIG. 100 illustrates a cross-sectional side view of the applicatorsystem of FIG. 92 , with the on-skin component in a deployed positionand the needle assembly retracted.

FIG. 101 illustrates a side view of another applicator system, accordingto some embodiments, with a side trigger member.

FIG. 102 illustrates another side view of the applicator system of FIG.101 , with the first and third portions shown in cross-section toillustrate the trigger mechanism.

FIG. 103 illustrates a side view of another applicator system, accordingto some embodiments, with an integrated side trigger.

FIG. 104 illustrates another side view of the applicator system of FIG.103 , with the first and third portions shown in cross-section and witha portion of the second portion removed to illustrate the triggermechanism.

FIG. 105 illustrates a perspective view of another applicator system,according to some embodiments, with a safety feature.

FIG. 106 illustrates a cross-sectional perspective view of a portion ofthe applicator system of FIG. 105 , with the safety feature in a lockedconfiguration.

FIG. 107 illustrates an enlarged view of the portion of the applicatorsystem of FIG. 106 , with the safety feature in a locked configuration.

FIG. 108 illustrates a cross-sectional perspective view of a portion ofthe applicator system of FIG. 105 , with the safety feature in areleased configuration.

FIG. 109 illustrates a cross-sectional perspective view of a portion ofthe applicator system of FIG. 105 , with the safety feature in areleased configuration and with the third portion moved distallyrelative to the first portion.

FIG. 110 illustrates a cross-sectional perspective view of an applicatorsystem, according to some embodiments, in a resting and locked state,with the on-skin component secured in a proximal position.

FIG. 111 illustrates a cross-sectional perspective view of theapplicator system of FIG. 110 , with the safety feature unlocked.

FIG. 112 illustrates a cross-sectional perspective view of theapplicator system of FIG. 110 , with the actuation member energized.

FIG. 113 illustrates a cross-sectional perspective view of theapplicator system of FIG. 110 , with the actuation member activated andwith the needle assembly and on-skin component deployed in a distalposition.

FIG. 114 illustrates a cross-sectional perspective view of theapplicator system of FIG. 110 , with the on-skin component in a deployedposition and separated from the retracted needle assembly.

FIG. 115 illustrates a perspective view of the needle assembly from thesystem of FIG. 110 , shown securing the on-skin component duringdeployment, with the base removed for purposes of illustration.

FIG. 116 illustrates another perspective view of the needle assemblyfrom the system of FIG. 110 , shown separated from the on-skincomponent, with the base removed for purposes of illustration.

FIG. 117 illustrates a perspective view of a portion of the system ofFIG. 100 .

FIG. 118 illustrates a perspective view of the sensor module of FIG. 100, before being coupled to the base.

FIG. 119 illustrates a perspective view of the sensor module of FIG. 100, after being coupled to the base.

FIG. 120 illustrates a side view of an on-skin component and base,according to some embodiments, prior to coupling of the on-skincomponent to the base.

FIG. 121 illustrates a perspective view of the on-skin component andbase of FIG. 120 , prior to coupling of the on-skin component to thebase.

FIG. 122 illustrates a side view of the on-skin component and base ofFIG. 120 , after coupling of the on-skin component to the base.

FIG. 123 illustrates a perspective view of a portion of anotherapplicator system, according to some embodiments, with an on-skincomponent coupled to a needle assembly in a proximal position.

FIG. 124 illustrates a perspective view of the on-skin component and theneedle assembly of FIG. 123 .

FIG. 125 illustrates a perspective view of a portion of the applicatorsystem shown in FIG. 123 , with the on-skin component separated from theneedle assembly.

FIG. 126 illustrates a perspective view of a portion of a securingmember, shown securing an on-skin component.

FIG. 127 illustrates a perspective view of a portion of the securingmember of FIG. 126 , with the sensor module of the on-skin componentshown in cross section, and illustrated with a decoupling feature of anapplicator assembly, according to some embodiments.

FIG. 128 illustrates a perspective view of the on-skin component of FIG.126 , after decoupling of the on-skin component from the securingmember.

FIG. 129 illustrates a perspective view of a portion of an applicatorassembly, according to some embodiments, with the second portion shownin cross section, and with a securing member shown securing an on-skincomponent in a proximal position.

FIG. 130 illustrates a perspective view of a portion of the applicatorassembly of FIG. 129 , shown with a portion of the securing member cutaway to better illustrate the configuration of the securing member.

FIG. 131 illustrates a perspective view of a portion of the applicatorassembly of FIG. 129 , after decoupling of the on-skin component fromthe needle assembly, shown with portions of the on-skin component andthe securing member cut away.

FIG. 132 illustrates a perspective view of a portion of an applicatorassembly, according to some embodiments, with the second portion shownin cross section, and with a securing member shown securing an on-skincomponent in a proximal position.

FIG. 133 illustrates a perspective view of the needle assembly andon-skin component of FIG. 132 , after decoupling of the on-skincomponent from the needle assembly.

FIG. 134 illustrates an exploded perspective view of a portion of anapplicator assembly, according to some embodiments, with a securingmember configured to releasably couple an on-skin component to a needleassembly.

FIG. 135 illustrates a perspective view of a portion of the applicatorassembly of FIG. 134 , with the needle assembly coupled to the on-skincomponent.

FIG. 136 illustrates a perspective view of a portion of the applicatorassembly of FIG. 134 , with the needle assembly decoupled from theon-skin component.

FIG. 137 illustrates a perspective view of an applicator assembly,according to some embodiments, with an on-skin component releasablysecured in a proximal position within the applicator assembly.

FIG. 138 illustrates a perspective view of the applicator assembly ofFIG. 137 , with the on-skin component released from securement.

FIG. 139 illustrates a perspective view of the on-skin component of FIG.137 , with the securing feature in a secured configuration.

FIG. 140 illustrates a perspective view of the on-skin component of FIG.137 , with the securing feature in a released configuration.

FIG. 141 illustrates a cross-sectional perspective view of a portion ofan applicator assembly, according to some embodiments, with the secondand third portions shown in cross section, and showing a base coupled toan applicator.

FIG. 142 illustrates a perspective view of another applicator assembly,according to some embodiments, showing a patch coupled to an applicator.

FIG. 143 illustrates a perspective view of the applicator assembly ofFIG. 142 , the patch decoupled from the applicator.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Although certain embodiments and examples are disclosed below, inventivesubject matter extends beyond the specifically disclosed embodiments toother alternative embodiments and/or uses, and to modifications andequivalents thereof. Thus, the scope of the claims appended hereto isnot limited by any of the particular embodiments described below. Forexample, in any method or process disclosed herein, the acts oroperations of the method or process may be performed in any suitablesequence and are not necessarily limited to any particular disclosedsequence. Various operations may be described as multiple discreteoperations in turn, in a manner that may be helpful in understandingcertain embodiments; however, the order of description should not beconstrued to imply that these operations are order dependent.Additionally, the structures, systems, and/or devices described hereinmay be embodied as integrated components or as separate components.

For purposes of comparing various embodiments, certain aspects andadvantages of these embodiments are described. Not necessarily all suchaspects or advantages are achieved by any particular embodiment. Thus,for example, various embodiments may be carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other aspects or advantages as mayalso be taught or suggested herein.

System Introduction

U.S. Patent Publication No. US-2013-0267811-A1, the entire contents ofwhich are incorporated by reference herein, explains how FIG. 1 is aschematic of a continuous analyte sensor system 100 attached to a host(e.g., a person). The analyte sensor system 100 communicates with otherdevices 110-113 (which can be located remotely from the host). Atranscutaneous analyte sensor system 102 comprising an on-skin sensorassembly 600 is fastened to the skin of a host via a base (not shown),which can be a disposable housing.

The system 102 includes a transcutaneous analyte sensor 200 and anelectronics unit (referred to interchangeably as “sensor electronics” or“transmitter”) 500 for wirelessly transmitting analyte information to areceiver. The receiver can be located remotely relative to the system102. In some embodiments, the receiver includes a display screen, whichcan display information to a person such as the host. Example receiversinclude computers such as smartphones, smartwatches, tablet computers,laptop computers, and desktop computers. In some embodiments, receiverscan be Apple Watches, iPhones, and iPads made by Apple Inc. In stillfurther embodiments, the system 102 can be configured for use inapplying a drug delivery device, such an infusion device, to the skin ofa patient. In such embodiments, the system can include a catheterinstead of, or in addition to, a sensor, the catheter being connected toan infusion pump configured to deliver liquid medicines or other fluidsinto the patient's body. In embodiments, the catheter can be deployedinto the skin in much the same manner as a sensor would be, for exampleas described herein.

In some embodiments, the receiver is mechanically coupled to theelectronics unit 500 to enable the receiver to receive data (e.g.,analyte data) from the electronics unit 500. To increase the convenienceto users, in several embodiments, the receiver does not need to bemechanically coupled to the electronics unit 500 and can even receivedata from the electronics unit 500 over great distances (e.g., when thereceiver is many feet or even many miles from the electronics unit 500).

During use, a sensing portion of the sensor 200 can be under the host'sskin and a contact portion of the sensor 200 can be electricallyconnected to the electronics unit 500. The electronics unit 500 can beengaged with a housing (e.g., a base) which is attached to an adhesivepatch fastened to the skin of the host.

The on-skin sensor assembly 600 may be attached to the host with use ofan applicator adapted to provide convenient and secure application. Suchan applicator may also be used for attaching the electronics unit 500 toa base, inserting the sensor 200 through the host's skin, and/orconnecting the sensor 200 to the electronics unit 500. Once theelectronics unit 500 is engaged with the base and the sensor 200 hasbeen inserted into the skin (and is connected to the electronics unit500), the sensor assembly can detach from the applicator.

The continuous analyte sensor system 100 can include a sensorconfiguration that provides an output signal indicative of aconcentration of an analyte. The output signal including (e.g., sensordata, such as a raw data stream, filtered data, smoothed data, and/orotherwise transformed sensor data) is sent to the receiver.

In some embodiments, the analyte sensor system 100 includes atranscutaneous glucose sensor, such as is described in U.S. PatentPublication No. US-2011-0027127-A1, the entire contents of which arehereby incorporated by reference. In some embodiments, the sensor system100 includes a continuous glucose sensor and comprises a transcutaneoussensor (e.g., as described in U.S. Pat. No. 6,565,509, as described inU.S. Pat. No. 6,579,690, as described in U.S. Pat. No. 6,484,046). Thecontents of U.S. Pat. Nos. 6,565,509, 6,579,690, and 6,484,046 arehereby incorporated by reference in their entirety.

In several embodiments, the sensor system 100 includes a continuousglucose sensor and comprises a refillable subcutaneous sensor (e.g., asdescribed in U.S. Pat. No. 6,512,939). In some embodiments, the sensorsystem 100 includes a continuous glucose sensor and comprises anintravascular sensor (e.g., as described in U.S. Pat. No. 6,477,395, asdescribed in U.S. Pat. No. 6,424,847). The contents of U.S. Pat. Nos.6,512,939, 6,477,395, and 6,424,847 are hereby incorporated by referencein their entirety.

Various signal processing techniques and glucose monitoring systemembodiments suitable for use with the embodiments described herein aredescribed in U.S. Patent Publication No. US-2005-0203360-A1 and U.S.Patent Publication No. US-2009-0192745-A1, the contents of which arehereby incorporated by reference in their entirety. The sensor canextend through a housing, which can maintain the sensor on the skin andcan provide for electrical connection of the sensor to sensorelectronics, which can be provided in the electronics unit 500.

In several embodiments, the sensor is formed from a wire or is in a formof a wire. A distal end of the wire can be sharpened to form a conicalshape (to facilitate inserting the wire into the tissue of the host).The sensor can include an elongated conductive body, such as a bareelongated conductive core (e.g., a metal wire) or an elongatedconductive core coated with one, two, three, four, five, or more layersof material, each of which may or may not be conductive. The elongatedsensor may be long and thin, yet flexible and strong. For example, insome embodiments, the smallest dimension of the elongated conductivebody is less than 0.1 inches, less than 0.075 inches, less than 0.05inches, less than 0.025 inches, less than 0.01 inches, less than 0.004inches, and/or less than 0.002 inches.

The sensor may have a circular cross section. In some embodiments, thecross section of the elongated conductive body can be ovoid,rectangular, triangular, polyhedral, star-shaped, C-shaped, T-shaped,X-shaped, Y-shaped, irregular, or the like. In some embodiments, aconductive wire electrode is employed as a core. To such an electrode,one or two additional conducting layers may be added (e.g., withintervening insulating layers provided for electrical isolation). Theconductive layers can be comprised of any suitable material. In certainembodiments, it may be desirable to employ a conductive layer comprisingconductive particles (i.e., particles of a conductive material) in apolymer or other binder.

In some embodiments, the materials used to form the elongated conductivebody (e.g., stainless steel, titanium, tantalum, platinum,platinum-iridium, iridium, certain polymers, and/or the like) can bestrong and hard, and therefore can be resistant to breakage. Forexample, in several embodiments, the ultimate tensile strength of theelongated conductive body is greater than 80 kPsi and less than 500kPsi, and/or the Young's modulus of the elongated conductive body isgreater than 160 GPa and less than 220 GPa. The yield strength of theelongated conductive body can be greater than 60 kPsi and less than 2200kPsi.

The electronics unit 500 can be releasably coupled to the sensor 200.The electronics unit 500 can include electronic circuitry associatedwith measuring and processing the continuous analyte sensor data. Theelectronics unit 500 can be configured to perform algorithms associatedwith processing and calibration of the sensor data. For example, theelectronics unit 500 can provide various aspects of the functionality ofa sensor electronics module as described in U.S. Patent Publication No.US-2009-0240120-A1 and U.S. Patent Publication No. US-2012-0078071-A1,the entire contents of which are incorporated by reference herein. Theelectronics unit 500 may include hardware, firmware, and/or softwarethat enable measurement of levels of the analyte via a glucose sensor,such as an analyte sensor 200.

For example, the electronics unit 500 can include a potentiostat, apower source for providing power to the sensor 200, signal processingcomponents, data storage components, and a communication module (e.g., atelemetry module) for one-way or two-way data communication between theelectronics unit 500 and one or more receivers, repeaters, and/ordisplay devices, such as devices 110-113. Electronics can be affixed toa printed circuit board (PCB), or the like, and can take a variety offorms. The electronics can take the form of an integrated circuit (IC),such as an Application-Specific Integrated Circuit (ASIC), amicrocontroller, and/or a processor. The electronics unit 500 mayinclude sensor electronics that are configured to process sensorinformation, such as storing data, analyzing data streams, calibratinganalyte sensor data, estimating analyte values, comparing estimatedanalyte values with time-corresponding measured analyte values,analyzing a variation of estimated analyte values, and the like.Examples of systems and methods for processing sensor analyte data aredescribed in more detail in U.S. Pat. Nos. 7,310,544, 6,931,327, U.S.Patent Publication No. 2005-0043598-A1, U.S. Patent Publication No.2007-0032706-A1, U.S. Patent Publication No. 2007-0016381-A1, U.S.Patent Publication No. 2008-0033254-A1, U.S. Patent Publication No.2005-0203360-A1, U.S. Patent Publication No. 2005-0154271-A1, U.S.Patent Publication No. 2005-0192557-A1, U.S. Patent Publication No.2006-0222566-A1, U.S. Patent Publication No. 2007-0203966-A1 and U.S.Patent Publication No. 2007-0208245-A1, the contents of which are herebyincorporated by reference in their entirety.

One or more repeaters, receivers and/or display devices, such as a keyfob repeater 110, a medical device receiver 111 (e.g., an insulindelivery device and/or a dedicated glucose sensor receiver), asmartphone 112, a portable computer 113, and the like can becommunicatively coupled to the electronics unit 500 (e.g., to receivedata from the electronics unit 500). The electronics unit 500 can alsobe referred to as a transmitter. In some embodiments, the devices110-113 transmit data to the electronics unit 500. The sensor data canbe transmitted from the sensor electronics unit 500 to one or more ofthe key fob repeater 110, the medical device receiver 111, thesmartphone 112, the portable computer 113, and the like. In someembodiments, analyte values are displayed on a display device.

The electronics unit 500 may communicate with the devices 110-113,and/or any number of additional devices, via any suitable communicationprotocol. Example communication protocols include radio frequency;Bluetooth; universal serial bus; any of the wireless local area network(WLAN) communication standards, including the IEEE 802.11, 802.15,802.20, 802.22 and other 802 communication protocols; ZigBee; wireless(e.g., cellular) telecommunication; paging network communication;magnetic induction; satellite data communication; and/or a proprietarycommunication protocol.

Additional sensor information is described in U.S. Pat. Nos. 7,497,827and 8,828,201. The entire contents of U.S. Pat. Nos. 7,497,827 and8,828,201 are incorporated by reference herein.

Any sensor shown or described herein can be an analyte sensor; a glucosesensor; and/or any other suitable sensor. A sensor described in thecontext of any embodiment can be any sensor described herein orincorporated by reference. Thus, for example, the sensor 138 shown inFIG. 7 can be an analyte sensor; a glucose sensor; any sensor describedherein; and any sensor incorporated by reference. Sensors shown ordescribed herein can be configured to sense, measure, detect, and/orinteract with any analyte.

As used herein, the term “analyte” is a broad term, and is to be givenits ordinary and customary meaning to a person of ordinary skill in theart (and is not to be limited to a special or customized meaning), andrefers without limitation to a substance or chemical constituent in abiological fluid (for example, blood, interstitial fluid, cerebralspinal fluid, lymph fluid, urine, sweat, saliva, etc.) that can beanalyzed. Analytes can include naturally occurring substances,artificial substances, metabolites, or reaction products.

In some embodiments, the analyte for measurement by the sensing regions,devices, systems, and methods is glucose. However, other analytes arecontemplated as well, including, but not limited to ketone bodies;Acetyl Co A; acarboxyprothrombin; acylcarnitine; adenine phosphoribosyltransferase; adenosine deaminase; albumin; alpha-fetoprotein; amino acidprofiles (arginine (Krebs cycle), histidine/urocanic acid, homocysteine,phenylalanine/tyrosine, tryptophan); andrenostenedione; antipyrine;arabinitol enantiomers; arginase; benzoylecgonine (cocaine);biotinidase; biopterin; c-reactive protein; carnitine; carnosinase; CD4;ceruloplasmin; chenodeoxycholic acid; chloroquine; cholesterol;cholinesterase; cortisol; testosterone; choline; creatine kinase;creatine kinase MM isoenzyme; cyclosporin A; d-penicillamine;de-ethylchloroquine; dehydroepiandrosterone sulfate; DNA (acetylatorpolymorphism, alcohol dehydrogenase, alpha 1-antitrypsin, cysticfibrosis, Duchenne/Becker muscular dystrophy, glucose-6-phosphatedehydrogenase, hemoglobin A, hemoglobin S, hemoglobin C, hemoglobin D,hemoglobin E, hemoglobin F, D-Punjab, beta-thalassemia, hepatitis Bvirus, HCMV, HIV-1, HTLV-1, Leber hereditary optic neuropathy, MCAD,RNA, PKU, Plasmodium vivax, sexual differentiation, 21-deoxycortisol);desbutylhalofantrine; dihydropteridine reductase; diptheria/tetanusantitoxin; erythrocyte arginase; erythrocyte protoporphyrin; esterase D;fatty acids/acylglycines; triglycerides; glycerol; free β-humanchorionic gonadotropin; free erythrocyte porphyrin; free thyroxine(FT4); free tri-iodothyronine (FT3); fumarylacetoacetase;galactose/gal-1-phosphate; galactose-1-phosphate uridyltransferase;gentamicin; glucose-6-phosphate dehydrogenase; glutathione; glutathioneperioxidase; glycocholic acid; glycosylated hemoglobin; halofantrine;hemoglobin variants; hexosaminidase A; human erythrocyte carbonicanhydrase I; 17-alpha-hydroxyprogesterone; hypoxanthine phosphoribosyltransferase; immunoreactive trypsin; lactate; lead; lipoproteins ((a),B/A-1, β); lysozyme; mefloquine; netilmicin; phenobarbitone; phenytoin;phytanic/pristanic acid; progesterone; prolactin; prolidase; purinenucleoside phosphorylase; quinine; reverse tri-iodothyronine (rT3);selenium; serum pancreatic lipase; sissomicin; somatomedin C; specificantibodies (adenovirus, anti-nuclear antibody, anti-zeta antibody,arbovirus, Aujeszky's disease virus, dengue virus, Dracunculusmedinensis, Echinococcus granulosus, Entamoeba histolytica, enterovirus,Giardia duodenalisa, Helicobacter pylori, hepatitis B virus, herpesvirus, HIV-1, IgE (atopic disease), influenza virus, Leishmaniadonovani, leptospira, measles/mumps/rubella, Mycobacterium leprae,Mycoplasma pneumoniae, Myoglobin, Onchocerca volvulus, parainfluenzavirus, Plasmodium falciparum, poliovirus, Pseudomonas aeruginosa,respiratory syncytial virus, rickettsia (scrub typhus), Schistosomamansoni, Toxoplasma gondii, Trepenoma pallidium, Trypanosomacruzi/rangeli, vesicular stomatis virus, Wuchereria bancrofti, yellowfever virus); specific antigens (hepatitis B virus, HIV-1); acetone(e.g., succinylacetone); acetoacetic acid; sulfadoxine; theophylline;thyrotropin (TSH); thyroxine (T4); thyroxine-binding globulin; traceelements; transferrin; UDP-galactose-4-epimerase; urea; uroporphyrinogenI synthase; vitamin A; white blood cells; and zinc protoporphyrin.

Salts, sugar, protein, fat, vitamins, and hormones naturally occurringin blood or interstitial fluids can also constitute analytes in certainembodiments. The analyte can be naturally present in the biologicalfluid or endogenous, for example, a metabolic product, a hormone, anantigen, an antibody, and the like. Alternatively, the analyte can beintroduced into the body or exogenous, for example, a contrast agent forimaging, a radioisotope, a chemical agent, a fluorocarbon-basedsynthetic blood, or a drug or pharmaceutical composition, including butnot limited to insulin; glucagon; ethanol; cannabis (marijuana,tetrahydrocannabinol, hashish); inhalants (nitrous oxide, amyl nitrite,butyl nitrite, chlorohydrocarbons, hydrocarbons); cocaine (crackcocaine); stimulants (amphetamines, methamphetamines, Ritalin, Cylert,Preludin, Didrex, PreState, Voranil, Sandrex, Plegine); depressants(barbiturates, methaqualone, tranquilizers such as Valium, Librium,Miltown, Serax, Equanil, Tranxene); hallucinogens (phencyclidine,lysergic acid, mescaline, peyote, psilocybin); narcotics (heroin,codeine, morphine, opium, meperidine, Percocet, Percodan, Tussionex,Fentanyl, Darvon, Talwin, Lomotil); designer drugs (analogs of fentanyl,meperidine, amphetamines, methamphetamines, and phencyclidine, forexample, Ecstasy); anabolic steroids; and nicotine. The metabolicproducts of drugs and pharmaceutical compositions are also contemplatedanalytes. Analytes such as neurochemicals and other chemicals generatedwithin the body can also be analyzed, such as, for example, ascorbicacid, uric acid, dopamine, noradrenaline, 3-methoxytyramine (3MT),3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA),5-hydroxytryptamine (5HT), 5-hydroxyindoleacetic acid (FHIAA), andintermediaries in the Citric Acid Cycle.

Many embodiments described herein use an adhesive (e.g., the adhesive126 in FIG. 7 ). One purpose of the adhesive can be to couple a base, asensor module, and/or a sensor to a host (e.g., to skin of the host).The adhesive can be configured for adhering to skin. The adhesive caninclude a pad (e.g., that is located between the adhesive and the base).Additional adhesive information, including adhesive pad information, isdescribed in U.S. patent application Ser. No. 14/835,603, which wasfiled on Aug. 25, 2015. The entire contents of U.S. patent applicationSer. No. 14/835,603 are incorporated by reference herein.

Distal Base Location

As noted above, systems can apply an on-skin sensor assembly to the skinof a host. The system can include a base that comprises an adhesive tocouple a glucose sensor to the skin.

In some applicators, the base is hidden deep inside the applicator untilthe user moves the needle distally with the base. One challenge withthis approach is that the insertion site (on the skin of the host) isnot ideally prepared for sensor and/or needle insertion. For example,the distal end of the applicator may be a hoop that presses against theskin. The pressure of the applicator on the skin can cause the area ofthe skin within the hoop to form a convex shape. In addition, the skinwithin the hoop can be too easily compressed such that the skin lackssufficient resilience and firmness. In this state, the sensor and/orneedle may press the skin downward without immediately piercing theskin, which may result in improper sensor and/or needle insertion.

In several embodiments, the base is coupled to a telescoping assemblysuch that the base protrudes from the distal end of the system while theglucose sensor is located remotely from the base and is located withinthe telescoping assembly. This configuration enables the base to preparethe insertion site of the skin for sensor and/or needle insertion (e.g.,by compressing the skin). Thus, these embodiments can dramaticallyimprove the reliability of sensor and/or needle insertion while reducingpain associated with sensor and/or needle insertion.

The system can hold the base in a position that is distal relative to aglucose sensor module such that a glucose sensor is not attached to thebase and such that the glucose sensor can move relative to the base.Moving the glucose sensor module distally towards the base can attachthe glucose sensor to the base. This movement can occur as a result ofcompressing an applicator.

FIG. 2 illustrates a perspective view of an applicator system 104 forapplying at least portions of an on-skin sensor assembly 600 (shown inFIG. 4 ) to skin of a host (e.g., a person). The system can include asterile barrier having a shell 120 and a cap 122. The cap 122 can screwonto the shell 120 to shield portions of the system 104 from externalcontaminants.

The electronics unit 500 (e.g., a transmitter having a battery) can bedetachably coupled to the sterile barrier shell 120. The rest of theapplicator system 104 can be sterilized, and then the electronics unit500 can be coupled to the sterile barrier shell 120 (such that theelectronics unit 500 is not sterilized with the rest of the applicatorsystem 104).

The user can detach the electronics unit 500 from the sterile barriershell 120. The user can also couple the electronics unit 500 to the base128 (as shown in FIG. 6 ) after the applicator system 104 places atleast a portion of a sensor in a subcutaneous position (for analytesensing).

Many different sterilization processes can be used with the embodimentsdescribed herein. The sterile barrier 120 and/or the cap 122 can blockgas from passing through (e.g., can be hermetically sealed). Thehermetic seal can be formed by threads 140 (shown in FIG. 3 ). Thethreads 140 can be compliant such that they deform to create a seal. Thethreads 140 can be located between the sterile barrier shell 120 and thecap 122.

The cap 122 can be made polypropylene and the shell 120 can be made frompolycarbonate (or vice versa) such that one of the cap 122 and the shell120 is harder than the other of the cap 122 and the 120. This hardness(or flexibility) difference enables one of the components to deform tocreate the thread 140 seal.

In some embodiments, at least one of the shell 120 and the cap 122includes a gas-permeable material to enable sterilization gases to enterthe applicator system 104. For example, as explained in the context ofFIG. 60 , the system can include a cover 272 h.

Referring now to FIG. 3 , the threads 140 can be configured such that aquarter rotation, at least 15 percent of a full rotation, and/or lessthan 50 percent of a full rotation uncouples the cap 122 from the shell120. Some embodiments do not include threads 140. The cap 122 can bepushed onto the shell 120 (e.g., during assembly) even in some threadedembodiments.

A cap 122 can be secured to the shell 120 by a frangible member 142configured such that removing the cap 122 from the shell 120 brakes thefrangible member 142. The frangible member 142 can be configured likethe safety ring (with a frangible portion) of a plastic soda bottle.Unscrewing the cap from the plastic soda bottle breaks the safety ringfrom the soda bottle's cap. This approach provides evidence oftampering. In the same way, the applicator system 104 can provide tamperevidence (due to the frangible member 142 being broken by removing thecap 122 from the shell 122).

U.S. Patent Publication No. US-2013-0267811-A1; U.S. Patent ApplicationNo. 62/165,837, which was filed on May 15, 2015; and U.S. PatentApplication No. 62/244,520, which was filed on Oct. 21, 2015, includeadditional details regarding applicator system embodiments. The entirecontents of U.S. Patent Publication No. US-2013-0267811-A1; U.S. PatentApplication No. 62/165,837; and U.S. Patent Application No. 62/244,520are incorporated by reference herein.

FIG. 3 illustrates a cross-sectional view of the system 104. A glucosesensor module 134 is configured to couple a glucose sensor 138 to thebase 128 (e.g., a “housing”). The telescoping assembly 132 is located ina proximal starting position such that the glucose sensor module 134 islocated proximally relative to the base 128 and remotely from the base128. The telescoping assembly 132 is configured such that collapsing thetelescoping assembly 132 connects the glucose sensor module 134 to thebase 128 via one or more mechanical interlocks (e.g., snap fits,interference features).

The sterile barrier shell 120 is coupled to a telescoping assembly 132.After removing the cap 122, the system 104 is configured such thatcompressing the sterile barrier shell 120 distally (while a distalportion of the system 104 is pressed against the skin) can insert asensor 138 (shown in FIG. 4 ) into the skin of a host to place thetranscutaneous, glucose analyte sensor 138. In many figures shownherein, the sterile barrier shell 120 and cap 122 are hidden to increasethe clarity of other features.

Collapsing the telescoping assembly 132 also pushes at least 2.5millimeters of the glucose sensor 138 out through a hole in the base 128such that at least 2.5 millimeters of the glucose sensor 138 that waspreviously located proximally relative to a distal end of the baseprotrudes distally out of the base 128. Thus, in some embodiments, thebase 128 can remain stationary relative to a distal portion of thetelescoping assembly 132 while the collapsing motion of the telescopingassembly 132 brings the glucose sensor module 134 towards the base 128and then couples the sensor module 134 to the base 128.

This relative motion between the sensor module 134 and the base 128 hasmany benefits, such as enabling the base to prepare the insertion siteof the skin for sensor and/or needle insertion (e.g., by compressing theskin). The starting position of the base 128 also enables the base 128to shield people from a needle, which can be located inside theapplicator system 104. For example, if the base 128 were directlycoupled to the sensor module 134 in the proximal starting position ofthe telescoping assembly, the needle may protrude distally from the base128. The exposed needle could be a potential hazard. In contrast, thedistal starting position of the base 128 enables the base 128 to protectpeople from inadvertent needle insertion. Needle protection isespecially important for caregivers (who are not the intended recipientsof the on-skin sensor assembly 600 shown in FIG. 4 ).

FIG. 4 illustrates a perspective view of the on-skin sensor assembly600, which includes the base 128. An adhesive 126 can couple the base128 to the skin 130 of the host. The adhesive 126 can be a foam adhesivesuitable for skin adhesion. A glucose sensor module 134 is configured tocouple a glucose sensor 138 to the base 128.

The applicator system 104 (shown in FIG. 2 ) can couple the adhesive 126to the skin 130. The system 104 can also secure (e.g., couple viamechanical interlocks such as snap fits and/or interference features)the glucose sensor module 134 to the base 128 to ensure the glucosesensor 138 is coupled to the base 128. Thus, the adhesive 126 can couplethe glucose sensor 138 to the skin 130 of the host.

After the glucose sensor module 134 is coupled to the base 128, a user(or an applicator) can couple the electronics unit 500 (e.g., atransmitter) to the base 128 via mechanical interlocks such as snap fitsand/or interference features. The electronics unit 500 can measureand/or analyze glucose indicators sensed by the glucose sensor 138. Theelectronics unit 500 can transmit information (e.g., measurements,analyte data, glucose data) to a remotely located device (e.g., 110-113shown in FIG. 1 ).

FIG. 5 illustrates a perspective view of the electronics unit 500coupled to the base 128 via mechanical interlocks such as snap fitsand/or interference features. Adhesive 126 on a distal face of the base128 is configured to couple the sensor assembly 600 to the skin. FIG. 6illustrates another perspective view of the electronics unit 500 coupledto the base 128.

Any of the features described in the context of FIGS. 1-6 can beapplicable to all aspects and embodiments identified herein. Forexample, many embodiments can use the on-skin sensor assembly 600 shownin FIG. 4 and can use the sterile barrier shell 120 shown in FIG. 2 .Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way, e.g., one, two, or three or more embodiments may be combinablein whole or in part. Further, any of the features of an embodiment maybe made optional to other aspects or embodiments. Any aspect orembodiment of a method can be performed by a system or apparatus ofanother aspect or embodiment, and any aspect or embodiment of a systemcan be configured to perform a method of another aspect or embodiment.

FIGS. 7-11 illustrate cross-sectional views of the applicator system 104from FIG. 3 . The sterile barrier shell 120 and the cap 134 are hiddenin FIGS. 7-11 to facilitate viewing the telescoping assembly 132.

The telescoping assembly 132 is part of a system for applying an on-skinsensor assembly 600 to skin of a host (shown in FIG. 4 ). Thetelescoping assembly 132 can apply portions of the system to the host.Additional portions of the system can be added to the on-skin sensorassembly 600 after the applicator system 104 couples initial portions ofthe sensor assembly 600 to the host. For example, as shown in FIG. 4 ,the electronics unit 500 (e.g., a transmitter) can be coupled to theon-skin sensor assembly 600 after the applicator system 104 (shown inFIG. 3 ) couples the base 128, the glucose sensor module 134, and/or theglucose sensor 138 to the skin 130 of the host.

In some embodiments, the applicator system 104 (shown in FIG. 3 )couples at least one, at least two, at least three, at least four,and/or all of the following items to the skin of the host: theelectronics unit 500, the glucose sensor module 134, the glucose sensor138, the base 128, and the adhesive 126. The electronics unit 500 can belocated inside the applicator system 104 such that the applicator system104 is configured to couple the electronics unit 500 to the skin of thehost.

FIG. 7 illustrates a telescoping assembly 132 having a first portion 150(e.g., a “pusher”) configured to move distally relative to a secondportion 152 (e.g., a “needle guard”) from a proximal starting positionto a distal position along a path 154. FIG. 7 illustrates thetelescoping assembly 132 in the proximal starting position. FIG. 8illustrates the telescoping assembly 132 moving between the proximalstarting position and the distal position. FIG. 11 illustrates thetelescoping assembly 132 in the distal position. The path 154 (shown inFIG. 7 ) represents the travel between the proximal starting positionand the distal position.

A first set of items can be immobile relative to the first portion 150,and a second set of items can be immobile relative to the second portion152 while the first set of items move relative to the second set ofitems.

Referring now to FIG. 7 , the glucose sensor 138 and the sensor module134 are coupled to the first portion 150 (e.g., such that they areimmobile relative to the first portion 150 during a proximal portion ofthe path 154). The base 128 is coupled to the second portion 152 suchthat the base 128 protrudes from a distal end of the system (e.g., thebase protrudes from a distal end of the telescoping assembly 132). Thebase 128 comprises adhesive 126 configured to eventually couple theglucose sensor 138 to the skin (e.g., after at least a portion of theglucose sensor 138 is rigidly coupled to the base 128).

In FIG. 7 , the glucose sensor 138 and the sensor module 134 are locatedwithin the second portion 152 while the base 128 protrudes from thedistal end of the system (e.g., from the distal end of the telescopingassembly 132) such that the system is configured to couple the glucosesensor 138 to the base 128 via moving the first portion 150 distallyrelative to the second portion 152. The progression shown in FIGS. 7-11illustrates moving the first portion 150 distally relative to the secondportion 152.

The sensor module 138 is coupled to a distal portion of the firstportion 150 such that moving the first portion 150 to the distalposition (as described above) couples the sensor module 134 to the base128. The glucose sensor 138 is coupled to the sensor module 134 (e.g.,immobile relative to the sensor module 134) while the first portion 150is located in the proximal starting position. The glucose sensor 138 caninclude a distally protruding portion and a proximal portion. Theproximal portion can be rigidly coupled to the sensor module 134 suchthat the proximal portion cannot move relative to the sensor module 134even though the distally protruding portion may bend relative to thesensor module 134.

A needle 156 (e.g., a “C-shaped” needle) is coupled to the first portion150 such that the glucose sensor 138 and the needle 156 move distallyrelative to the base 128 and relative to the second portion 152. Thesystem can further comprise a needle release mechanism 158 configured toretract the needle 156 proximally.

The needle 156 can have many different forms. Many different types ofneedles 156 can be used with the embodiments described herein. FIGS.51-55 illustrate various needle embodiments that can be used with any ofthe embodiments described herein.

The needle 156 can guide the sensor 138 into the skin of the host. Adistal portion of the sensor 138 can be located in a channel of theneedle 156 (as shown in FIG. 42 ). Sometimes, a distal end of the sensor138 sticks out of the needle 156 and gets caught on tissue of the hostas the sensor 138 and needle 156 are inserted into the host. As aresult, the sensor 138 may buckle and fail to be inserted deeply enoughinto the subcutaneous tissue. In other words, in some embodiments, thesensor wire must be placed within the channel of the C-shaped needle 156to be guided into the tissue and must be retained in the channel 330during deployment.

The risk of the sensor 138 sticking out of the channel 330 (and therebyfailing to be property inserted into the host) can be greatly diminishedby the embodiment illustrated in FIG. 51 . In this embodiment, adhesive376 bonds a distal portion of the glucose sensor 138 into the channel330 of the needle 156. Retracting the needle 156 can break the bond ofthe adhesive 376 to enable a distal portion of the sensor 138 to stay ina subcutaneous location while the needle 156 is retracted (and evenafter the needle 156 is retracted).

The risk of the sensor 138 sticking out of the channel 330 (and therebyfailing to be property inserted into the host) can be greatly diminishedby the embodiment illustrated in FIGS. 52 and 53 . In this embodiment,the needle 156 a comprises two sides, which can be separated by slots378. The sensor 138 can have a width that is larger than the width ofthe slots 378 such that the sensor 138 cannot come out of the channel330 a until the two sides of the needle 156 a are moved apart (to widenthe slots 378).

The embodiment illustrated in FIG. 54 can be used with any of the otherembodiments described herein. The needle 156 b includes a ramp 380 atthe distal end of the channel 330 b. The distal end of the needle 156 bcan include a conical tip 382. The ramp 380 can be configured to pushthe sensor 138 out of the channel 330 b of the needle 156 b as theneedle 156 b is retracted into the telescoping assembly 132 (shown inFIG. 7 ).

FIG. 55 illustrates cross sectional views of different needles 156 c,156 d, 156 e, 156 f, which can be used as needle 156 in FIG. 7 or in anyother embodiment described herein. Needle 156 c includes an enclosedchannel 330 c. Needles 156 d, 156 e, 156 f are C-needles, although manyother C-needle shapes can be used in several embodiments. The ends ofthe needle 156 d can be angled relative to each other. In someembodiments, the ends of the needle can be angled away from each other,in an opposite fashion as shown by 156 d. In some embodiments, the endsof the needle can have flared edges, in which the flared edges arerounded to prevent the sensor from contacting sharp edges. The ends ofthe needle 156 e can be parallel and/or flat relative to each other. Theoutside portion of the channel 330 f can be formed by walls that arestraight and/or parallel to each other (rather than by curved walls asis the case for other needles 156 d, 156 e). Some needles 156 d can bemanufactured via laser cutting, some needles 156 e can be manufacturedvia wire electrical discharge machining (“EDM”), and some needles 156 fcan be manufactured via stamping.

As shown in FIG. 7 , a needle hub 162 is coupled to the needle 156. Theneedle hub includes release features 160 that protrude outward. In someembodiments, the release features can comprise one, two, or moreflexible arms. Outward ends 164 of the release features 160 catch oninwardly facing overhangs 166 (e.g., undercuts, detents) of the firstportion 150 such that moving the first portion 150 distally relative tothe second portion 152 causes the needle retraction mechanism 158 tomove distally until a release point.

At the release point, proximal protrusions 170 of the second portion 152engage the release features 160 (shown in FIG. 9 ), which forces therelease features 160 to bend inward until the release features 160 nolonger catch on the overhangs 166 of the first portion 150 (shown inFIG. 10 ). Once the release features 160 no longer catch on theoverhangs 166 of the first portion 150, the spring 234 of the needleretraction mechanism 158 pushes the needle 156 and the needle hub 162proximally relative to the first portion 150 and relative to the secondportion 152 until the needle no longer protrudes distally from the base128 and is completely hidden inside the telescoping assembly 132 (shownin FIG. 11 ).

The needle 156 can be removed from the embodiment illustrated in FIG. 7to make a needle-free embodiment. Thus, a needle 156 is not used in someembodiments. For example, a distal end of the glucose sensor 138 can beformed in a conical shape to enable inserting the glucose sensor 138into the skin without using a needle 156. Unless otherwise noted, theembodiments described herein can be formed with or without a needle 156.

In several embodiments, a needle can help guide the glucose sensor 138(e.g., at least a distal portion of the glucose sensor) into the skin.In some embodiments, a needle is not part of the system and is not usedto help guide the glucose sensor 138 into the skin. In needleembodiments and needle-free embodiments, skin piercing is an importantconsideration. Failing to properly pierce the skin can lead to improperplacement of the glucose sensor 138.

Tensioning the skin prior to piercing the skin with the glucose sensor138 and/or the needle 156 can dramatically improve the consistency ofachieving proper placement of the glucose sensor 138. Tensioning theskin can be accomplished by compressing the skin with a distallyprotruding shape (e.g., a convex shape) prior to piercing the skin andat the moment of piercing the skin with the glucose sensor 138 and/orthe needle 156.

FIG. 12A illustrates a portion of the cross section shown in FIG. 7 .The base 128 includes an optional distally facing protrusion 174 locateddistally relative to the second portion 152 (and relative to the rest ofthe telescoping assembly 132). The distal protrusion 174 is convex andis shaped as a dome. In some embodiments, the distal protrusion 174 hasblock shapes, star shapes, and cylindrical shapes. Several base 128embodiments do not include the protrusion 174.

The distal protrusion 174 can be located farther distally than any otherportion of the base 128. The distal protrusion 174 can extend through ahole 176 in the adhesive 126 (as also shown in FIG. 5 ). A distalportion of the convex protrusion 174 can be located distally relative tothe adhesive 126 while a proximal portion of the convex protrusion 174is located proximally relative to the adhesive 126.

The distal protrusion 174 has a hole 180 through which the needle 156and/or the glucose sensor 138 can pass. The distal protrusion 174 cancompress the skin such that the distal protrusion 174 is configured toreduce a resistance of the skin to piercing.

FIG. 12B illustrates a cross sectional view of a base 128 b that isidentical to the base 128 illustrated in FIGS. 7 and 12B except for thefollowing features: The base 128 b does not include a protrusion 174.The base 128 b includes a funnel 186 (e.g., a radius) on the distal sideof the hole 180 b.

Like the embodiment shown in FIG. 12A, the sensor 138 (e.g., an analytesensor) and/or the needle 156 (shown in FIG. 12A) can pass through thehole 180 b (shown in FIG. 12B). The funnels 182, 186 can be mirrorimages of each other or can be different shapes. The base 128 b can beused with any of the embodiments described herein.

FIG. 13 illustrates a perspective view of a portion of the adhesive 126.The needle 156 can have many different shapes and cross sections. Insome embodiments, the needle 156 includes a slot 184 (e.g., the channel330 shown in FIGS. 42 and 43 ) into which at least a portion of theglucose sensor 138 can be placed.

The needle 156 having a slot 184 passes through the hole 180 of thedistal protrusion and through the hole 176 of the adhesive 126. Aportion of the glucose sensor 138 is located in the slot 184 such thatthe needle 156 is configured to move distally relative to the base 128(shown in FIG. 12A) without dislodging the portion of the glucose sensor138 from the slot 184. The distal protrusion 174 is convex such that thedistal protrusion 174 is configured to tension the skin while the firstportion 150 moves distally relative to the second portion 152 of thetelescoping assembly 132 (shown in FIG. 7 ) to prepare the skin forpiercing.

As mentioned above, the adhesive 126 comprises a hole 176 through whichat least a portion of the distal protrusion 174 of the base 128 canpass. The distal protrusion 174 is located within the hole 176 of theadhesive 126 such that the distal protrusion 174 can tension at least aportion of the skin within the second hole (e.g., located under the hole176). The hole 176 can be circular or any other suitable shape. The hole176 can be sized such that at least a majority of the distal protrusion174 extends through the hole 176. A perimeter of the hole 176 can belocated outside of the distal protrusion 174 such that the perimeter ofthe hole 176 is located radially outward relative to a perimeter of theprotrusion 174 where the protrusion 174 connects with the rest of thebase 128.

In some embodiments, the hole 176 of the adhesive 126 is large enoughthat the adhesive 126 does not cover any of the distal protrusion 174.In some embodiments, the adhesive 126 covers at least a portion of oreven a majority of the distal protrusion 174. Thus, the adhesive 126does not have to be planar and can bulge distally in an area over thedistal protrusion 174.

In several embodiments, the adhesive 126 has a non-uniform thicknesssuch that the thickness of the adhesive 126 is greater in an areasurrounding a needle exit area than in other regions that are fartherradially outward from the needle exit area. Thus, the distal protrusion174 can be part of the adhesive 126 rather than part of the base 128.However, in several embodiments, the base 128 comprises the adhesive126, and the distal protrusion 174 can be formed by the plastic of thebase 128 or by the foam adhesive 126 of the base 128.

The needle 156 includes a distal end 198 and a heel 194. The heel 194 isthe proximal end of the angled portion of the needle's tip. The purposeof the angled portion is to form a sharp end to facilitate penetratingtissue. The sensor 138 has a distal end 208.

During insertion of the needle 156 and the sensor 138 into the tissue;as the needle 156 and the sensor 138 first protrude distally from thesystem; and/or while the needle 156 and the sensor 138 are locatedwithin the telescoping assembly, the end 208 of the sensor 138 can belocated at least 0.1 millimeter proximally from the heel 194, less than1 millimeter proximally from the heel 194, less than 3 millimetersproximally from the heel 194, and/or within plus or minus 0.5millimeters of the heel 194; and/or the end 208 of the sensor 138 can belocated at least 0.3 millimeters proximally from the distal end 198 ofthe needle 156 and/or less than 2 millimeters proximally from the distalend 198.

Referring now to FIG. 12A, the distal protrusion 174 can protrude atleast 0.5 millimeters and less than 5 millimeters from the distalsurface of the adhesive 126. In embodiments where the adhesive 126 has anon-planar distal surface, the distal protrusion 174 can protrude atleast 0.5 millimeters and less than 5 millimeters from the averagedistal location of the adhesive 126.

As described above, in some embodiments the base is coupled to atelescoping assembly such that the base protrudes from the distal end ofthe system while the glucose sensor is located remotely from the baseand is located within the telescoping assembly. In other embodiments,however, the base is coupled to a telescoping assembly such that thebase is located completely inside the telescoping assembly and the basemoves distally with the sensor as the first portion is moved distallyrelative to the second portion of the telescoping assembly.

For example, FIG. 59 illustrates a base 128 coupled to the sensor module134 and to the sensor 138 while the first portion 150 of the telescopingassembly 132 f is located in the proximal starting position. The base128 moves distally as the first portion 150 is moved distally relativeto the second portion 152. The base 128 can be coupled to a distal endportion of the first portion 150 while the first portion 150 is locatedin the proximal starting position. All of the features and embodimentsdescribed herein can be configured and used with the base 128positioning described in the context of FIG. 59 .

All of the embodiments described herein can be used with the basecoupled to a telescoping assembly such that the base is locatedcompletely inside the telescoping assembly and the base moves distallywith the sensor as the first portion is moved distally relative to thesecond portion of the telescoping assembly. All of the embodimentsdescribed herein can be used with the base coupled to a telescopingassembly such that the base protrudes from the distal end of the systemwhile the glucose sensor is located remotely from the base and islocated within the telescoping assembly.

Sensor Module Docking and Base Detachment

As explained above, maintaining the base against the skin duringinsertion of the sensor and/or needle enables substantial medicalbenefits. Maintaining the base against the skin, however, cannecessitate moving the sensor relative to the base during the insertionprocess. Once inserted, the sensor needs to be coupled to the base toprevent the sensor from inadvertently dislodging from the base. Thus,there is a need for a system that enables the sensor to move relative tothe base and also enables locking the sensor to the base (without beingoverly burdensome on users).

Maintaining the base against the skin during the distal movement of thesensor and/or needle is enabled in many embodiments by unique couplingsystems that secure the sensor (and the sensor module) to a firstportion of a telescoping assembly and secure the base to a secondportion of the telescoping assembly. Moving the first portion towardsthe second portion of the telescoping assembly can align the sensor withthe base while temporarily holding the sensor. Then, the system cancouple the sensor to the base. Finally, the system can detach the baseand sensor from the telescoping assembly (which can be disposable orreusable with a different sensor).

As illustrated in FIG. 4 , the sensor module 134 and the glucose sensor138 are not initially coupled to the base 128. Coupling the sensormodule 134 and the glucose sensor 138 to the base 128 via compressingthe telescoping assembly 132 and prior to detaching the base 128 fromthe telescoping assembly 132 can be a substantial challenge, yet isenabled by many of the embodiments described herein.

As illustrated in FIGS. 7 and 14 , the sensor module 134 (and theglucose sensor 138) can be located remotely from the base 128 eventhough they are indirectly coupled via the telescoping assembly 132. Inother words, the sensor module 134 (and the glucose sensor 138) can becoupled to the first portion 150 of the telescoping assembly 132 whilethe base 128 is coupled to the second portion 152 of the telescopingassembly 132. In this state, the sensor module 134 and the glucosesensor 138 can move relative to the base 128 (e.g., as the sensor module134 and the glucose sensor 138 move from the proximal starting positionto the distal position along the path to “dock” the sensor module 134and the glucose sensor 138 to the base 128).

After the sensor module 134 and the glucose sensor 138 are “docked” withthe base 128, the system can detach the base 128 from the telescopingassembly 132 to enable the sensor module 134, the glucose sensor 138,and the base 128 to be coupled to the skin by the adhesive 126 while thetelescoping assembly 132 and other portions of the system are discarded.

As shown in FIG. 7 , the sensor module 134 is coupled to the firstportion 150 and is located at least 5 millimeters from the base 128while the first portion 150 is in the proximal starting position. Thesystem is configured such that moving the first portion 150 to thedistal position couples the sensor module 134 to the base 128 (as shownin FIG. 11 ). The glucose sensor 138 is coupled to the sensor module 134while the first portion 150 is located in the proximal startingposition. The glucose sensor 138 is located within the second portion152 while the base 128 protrudes from the distal end of the system.

Arrow 188 illustrates the proximal direction in FIG. 7 . Arrow 190illustrates the distal direction in FIG. 7 . Line 172 illustrates ahorizontal orientation. As used herein, horizontal means within plus orminus 20 degrees of perpendicular to the central axis 196.

FIG. 15 illustrates a perspective view of a cross section of portions ofthe system shown in FIG. 7 . The cross section cuts through the hole 180of the base 128. Visible portions include the sensor module 134, thesensor 138, a seal 192, the needle 156, the base 128, and the adhesive126. The sensor module 134 is in the proximal starting position. Theseal 192 is configured to block fluid (e.g., bodily fluid) from enteringthe glucose sensor module 134.

The glucose sensor 138 is mechanically coupled to the sensor module 134.The glucose sensor 138 runs into an interior portion of the sensormodule 134 and is electrically coupled to interconnects in the interiorportion of the sensor module 134. The interconnects are hidden in FIG.15 to facilitate seeing the proximal portion of the glucose sensor 138inside the interior portion of the sensor module 134. Many otherportions of the system are also hidden in FIG. 15 to enable clearviewing of the visible portions.

In many embodiments, the sensor module 134 moves from the position shownin FIG. 15 until the sensor module 134 snaps onto the base 128 via snapfits that are described in more detail below. FIG. 11 illustrates thesensor module 134 snapped to the base 128. This movement from theproximal starting position to the “docked” position can be accomplishedby moving along the path 154 (shown in FIG. 7 and illustrated by theprogression in FIGS. 7-11 ). (The arrow representing the path 154 is notnecessarily drawn to scale.)

Referring now to FIGS. 7 and 15 , during a first portion of the path154, the sensor module 134 is immobile relative to the first portion150, and the base 128 is immobile relative to the second portion 152 ofthe telescoping assembly 132. During a second portion of the path 154,the system is configured to move the first portion 150 distally relativeto the second portion 152; to move the sensor module 134 towards thebase 128; to move at least a portion of the sensor 138 through a hole180 in the base 128; to couple the sensor module 134 to the base 128;and to enable the coupled sensor module 134 and the base 128 to detachfrom the telescoping assembly 132.

FIG. 7 illustrates a vertical central axis 196 oriented from a proximalend to the distal end of the system. (Part of the central axis 196 ishidden in FIG. 7 to avoid obscuring the arrow that represents the path154 and to avoid obscuring the needle 156.)

FIG. 15 illustrates a flex arm 202 of the sensor module 134. The flexarm 202 is oriented horizontally and is configured to secure the sensormodule 134 to a protrusion of the base 128. In some embodiments, theflex arm 202 is an alignment arm to prevent and/or impede rotation ofthe sensor module 134 relative to the base 128.

FIG. 16 illustrates a perspective view of a cross section in which thesensor module 134 is coupled to the base 128 via flex arms 202.Interconnects 204 protrude proximally to connect the sensor module 134to the electronics unit 500 (e.g., a transmitter).

Referring now to FIGS. 15 and 16 , the flex arms 202 extend from anouter perimeter of the sensor module 134. The base 128 comprisesprotrusions 206 that extend proximally from a planar, horizontal portionof the base 128.

Referring now to FIG. 16 , each of the proximal protrusions 206 of thebase 128 are coupled to a flex arm 202 of the sensor module 134. Thus,the coupling of the proximal protrusions 206 to the flex arms 202couples the sensor module 134 to the base 128.

Each proximal protrusion 206 can include a locking protrusion 212 thatextends at an angle of at least 45 degrees from a central axis of eachproximal protrusion 206. In some embodiments, the locking protrusions212 extend horizontally (e.g., as shown in FIG. 15 ). Each horizontallocking protrusion 212 is coupled to an end portion 210 of a flexiblearm 202.

The end portion 210 of each flexible arm 202 can extend at an anglegreater than 45 degrees and less than 135 degrees relative to a centralaxis of the majority of the flexible arm 202. The end portion 210 ofeach flexible arm 202 can include a horizontal locking protrusion (e.g.,as shown in FIG. 15 ).

In FIGS. 15 and 16 , a first horizontal locking protrusion is coupled toan end portion 210 of the first flexible arm 202. A second horizontallocking protrusion 212 is coupled to the first proximal protrusion 206of the base 128. In FIG. 16 , the first horizontal locking protrusion islocated distally under the second horizontal locking protrusion 212 tosecure the sensor module 134 to the base 128. The system is configuredsuch that moving the first portion 150 of the telescoping assembly 132to the distal position (shown in FIG. 11 ) causes the first flex arm 202to bend to enable the first horizontal locking protrusion of the flexarm 202 to move distally relative to the second horizontal lockingprotrusion 212. Thus, the flex arm 202 is secured between the lockingprotrusion 212 and the distal face of the base 128.

At least a portion of the flex arm 202 (e.g., the end portion 210) islocated distally under the horizontal locking protrusion 212 of the base128 to secure the sensor module 134 to the base 128. The system isconfigured such that moving the first portion 150 of the telescopingassembly 132 to the distal position causes the flex arm 202 (e.g., theend portion 210) to bend away (e.g., outward) from the rest of thesensor module 134 to enable the horizontal locking protrusion of theflex arm 202 to go around the locking protrusion 212 of the proximalprotrusion 206. Thus, at least a portion of the flex arm 202 can movedistally relative to the horizontal locking protrusion 212 of theproximal protrusion 206 of the base 128.

The sensor module 134 can have multiple flex arms 202 and the base canhave multiple proximal protrusions 206 configured to couple the sensormodule 134 to the base 128. In some embodiments, a first flex arm 202 islocated on an opposite side of the sensor module 134 relative to asecond flex arm 202 (e.g., as shown in FIGS. 15 and 16 ).

In some embodiments, the base 128 comprises flex arms (e.g., like theflex arms 202 shown in FIGS. 15 and 16 ) and the sensor module 134comprises protrusions that couple to the flex arms of the base 128. Theprotrusions of the sensor module 134 can be like the protrusions 206shown in FIGS. 15 and 16 except that, in several embodiments, theprotrusions extend distally towards the flex arms of the base 128. Thus,the base 128 can be coupled to the sensor module 134 with flex arms andmating protrusions regardless of whether the base 128 or the sensormodule 134 includes the flex arms.

In several embodiments, a sensor module is coupled to the glucosesensor. The system comprises a vertical central axis oriented from aproximal end to the distal end of the system. The base comprises a firstflex arm that is oriented horizontally and is coupled to the sensormodule. The sensor module comprises a first distal protrusion coupled tothe first flex arm to couple the sensor module to the base. A firsthorizontal locking protrusion is coupled to an end portion of the firstflexible arm. A second horizontal locking protrusion is coupled to thefirst distal protrusion of the sensor module. The second horizontallocking protrusion is located distally under the first horizontallocking protrusion to secure the sensor module to the base. The systemis configured such that moving the first portion of the telescopingassembly to the distal position causes the first flex arm to bend toenable the second horizontal locking protrusion to move distallyrelative to the first horizontal locking protrusion. The sensor modulecomprises a second distal protrusion coupled to a second flex arm of thebase. The first distal protrusion is located on an opposite side of thesensor module relative to the second distal protrusion.

Docking the sensor module 134 to the base 128 can include securing thesensor module 134 to the first portion 150 of the telescoping assembly132 while the first portion 150 moves the sensor module 134 towards thebase 128. This securing of the sensor module 134 to the first portion150 of the telescoping assembly 132 needs to be reliable, but temporaryso the sensor module 134 can detach from the first portion 150 at anappropriate stage. The structure that secures the sensor module 134 tothe first portion 150 of the telescoping assembly 132 generally needs toavoid getting in the way of the docking process.

FIG. 17 illustrates a cross-sectional view of the first portion 150 ofthe telescoping assembly 132. FIG. 17 shows the glucose sensor module134 and the needle 156. Some embodiments do not include the needle 156.Many items are hidden in FIG. 17 to provide a clear view of the flexarms 214, 216 of the first portion 150.

The first portion 150 comprises a first flex arm 214 and a second flexarm 216 that protrude distally and latch onto the sensor module 134 toreleasably secure the sensor module 134 to the first portion 150 whilethe first portion 150 is in the proximal starting position (shown inFIG. 7 ). The flex arms 214, 216 can couple to an outer perimeter of thesensor module 134 such that distal ends of the flex arms 214, 216 wraparound a distal face of the sensor module 134. In some embodiments, thedistal ends of the flex arms 214, 216 are located distally of the sensormodule 134 while the first portion 150 is in the proximal startingposition.

The base 128 is hidden in FIG. 17 , but in the state illustrated in FIG.17 , the sensor module 134 is located remotely from the base 128 toprovide a distance of at least 3 millimeters from the sensor module 134to the base 128 while the first portion 150 is in the proximal startingposition. This distance can be important to enable the base to rest onthe skin as the needle 156 and/or the glucose sensor 138 pierce the skinand advance into the skin during the transcutaneous insertion.

Referring now to FIGS. 7 and 17 , the sensor module 134 is locatedwithin the second portion 152 while the base 128 protrudes from thedistal end of the system such that the system is configured to couplethe sensor module 134 to the base 128 via moving the first portion 150distally relative to the second portion 152. The sensor module 134 islocated within the second portion 152 while the base 128 protrudes fromthe distal end of the system even though the sensor module 134 ismoveable relative to the second portion 152 of the telescoping assembly132. Thus, the first portion 150 moves the sensor module 134 through aninterior region of the second portion 152 of the telescoping assembly132 without moving the base 128 through the interior region of thesecond portion 152.

The system comprises a vertical central axis 196 oriented from aproximal end to the distal end of the system. The first flex arm 214 andthe second flex arm 216 of the first portion 150 secure the sensormodule 134 to the first portion 150 such that the sensor module 134 isreleasably coupled to the first portion 150 with a first verticalholding strength (measured along the vertical central axis 196).

As shown in FIGS. 15 and 16 , the sensor module 134 is coupled to thebase 128 via at least one flex arm 202 such that the sensor module 134is coupled to the base 128 with a second vertical holding strength. Theflex arms 202 can extend from an outer perimeter of the sensor module134. The flex arms 202 can be part of the base 128.

Referring now to FIG. 17 , in some embodiments, the second verticalholding strength is greater than the first vertical holding strengthsuch that continuing to push the first portion 150 distally once thesensor module 134 is coupled to the base 128 overcomes the first andsecond flex arms 214, 216 of the first portion 150 to detach the sensormodule 134 from the first portion 150.

In some embodiments, the second vertical holding strength is at least 50percent greater than the first vertical holding strength. In severalembodiments, the second vertical holding strength is at least 100percent greater than the first vertical holding strength. In someembodiments, the second vertical holding strength is less than 400percent greater than the first vertical holding strength.

FIG. 6 illustrates the on-skin sensor assembly 600 in a state where itis attached to a host. The on-skin sensor assembly 600 can include theglucose sensor 138 and/or the sensor module 134 (shown in FIG. 7 ). Insome embodiments, the on-skin sensor assembly 600 includes the needle156. In several embodiments, however, the on-skin sensor assembly 600does not include the needle 156.

As explained above, maintaining the base against the skin duringinsertion of the sensor and/or needle enables substantial medicalbenefits. Maintaining the base against the skin, however, can complicatedetaching the base from the applicator. For example, in some prior-artsystems, the base detaches after the base moves downward distally with aneedle. This relatively long travel can enable several base detachmentmechanisms. In contrast, when the base is maintained in a stationaryposition as the needle moves towards the base, releasing the base can beproblematic.

Many embodiments described herein enable maintaining the base 128against the skin during insertion of the sensor 138 and/or the needle156. As mentioned above in the context of FIGS. 7-11 , after the sensormodule 134 is coupled to the base 128, the sensor module 134 and thebase 128 need to detach from the telescoping assembly 132 to secure theglucose sensor 138 to the host and to enable the telescoping assembly tobe thrown away, recycled, or reused.

As shown in FIGS. 7-11 , several embodiments hold the base 128 in astationary position relative to the second portion 152 of thetelescoping assembly 132 as the sensor module 134 moves towards the base128. Referring now to FIG. 18 , once the sensor module 134 is attachedto the base 128, the system can release the base 128 by bending flexarms 220 that couple the base 128 to the second portion 152. FIG. 18shows the system in a state prior to the sensor module 134 docking withthe base 128 to illustrate distal protrusions 222 of the first portion150 aligned with the flex arms 220 such that the distal protrusions 222are configured to bend the flex arms 220 (via the distal protrusions 222contacting the flex arms 220).

The distal protrusions 222 bend the flex arms 220 to detach the base 128from the telescoping assembly 132 (shown in FIG. 7 ) after the sensormodule 134 is coupled to the base 128 (as shown in FIGS. 11 and 16 ).The flex arms 220 can include a ramp 224. A distal end of the distalprotrusions 222 can contact the ramp 224 and then can continue movingdistally to bend the flex arm 220 as shown by arrow 228 in FIG. 18 .This bending can uncouple the flex arm 220 from a locking feature 230 ofthe base 128. This unlocking is accomplished by the first portion 150moving distally relative to the second portion 152, which causes thedistal protrusions 222 to move as shown by arrow 226.

An advantage of the system shown in FIG. 18 is that the unlockingmovement (of the arm 220 bending as shown by arrow 228) is perpendicular(within plus or minus 20 degrees) to the input force (e.g., asrepresented by arrow 226). Thus, the system is designed such that themaximum holding capability (e.g., of the locking feature 230) can bemany times greater than the force necessary to unlock the arm 220 fromthe base 128. As a result, the system can be extremely reliable andinsensitive to manufacturing variability and normal use variations.

In contrast, if the holding force and the unlocking force were orientedalong the same axis (e.g., within plus or minus 20 degrees), the holdingforce would typically be equal to or less than the unlocking force.However, the unique structure shown in FIG. 18 allows the holding forceto be at least two times larger (and in some cases at least four timeslarger) than the unlocking force. As a result, the system can preventinadvertent unlocking of the base 128 while having an unlocking forcethat is low enough to be easily provided by a user or by another part ofthe system (e.g., a motor).

Another advantage of this system is that it controls the locking andunlocking order of operation. In other words, the structure precludespremature locking and unlocking. In a medical context, this control isextremely valuable because reliability is so critical. For example, inseveral embodiments, the process follows this order: The sensor module134 couples to the base 128. Then, the first portion 150 releases thesensor module 134. Then, the second portion 152 releases the base 128.In several embodiments, the vertical locations of various locking andunlocking structures are optimized to ensure this order is the onlyorder that is possible as the first portion 150 moves from the proximalstarting position to the distal position along the path describedpreviously. (Some embodiments use different locking and unlocking ordersof operation.)

FIG. 7 illustrates the base 128 protruding from the distal end of thesystem while the first portion 150 of the telescoping assembly 132 islocated in the proximal starting position. The sensor module 134 and atleast a majority of the glucose sensor 138 are located remotely relativeto the base 128. The system is configured to couple the sensor module134 and the glucose sensor 138 to the base 128 via moving the firstportion 150 distally relative to the second portion 152.

Referring now to FIGS. 18 and 19 , the base 128 comprises a first radialprotrusion 230 (e.g., a locking feature) releasably coupled with a firstvertical holding strength to a second radial protrusion 232 (e.g., alocking feature) of the second portion 152 of the telescoping assembly132 (shown in FIG. 7 ). The first radial protrusion 230 protrudes inwardand the second radial protrusion protrudes outward 232. The system isconfigured such that moving the first portion 150 to the distal positionmoves the second radial protrusion 232 relative to the first radialprotrusion 230 to detach the base 128 from the telescoping assembly 132.

The first portion 150 of the telescoping assembly 132 comprises a firstarm 222 that protrudes distally. The second portion 152 of thetelescoping assembly 132 comprises a second flex arm 220 that protrudesdistally. The first arm 222 and the second flex arm 220 can be orientedwithin 25 degrees of each other (as measured between their centralaxes). The system is configured such that moving the first portion 150from the proximal starting position to the distal position along thepath 154 (shown in FIG. 7 ) causes the first arm 222 to deflect thesecond flex arm 220, and thereby detach the second flex arm 220 from thebase 128 to enable the base 128 to decouple from the telescopingassembly 132 (shown in FIG. 7 ). Thus, the flex arm 220 is configured toreleasably couple the second portion 152 to the base 128.

When the first portion 150 is in the proximal starting position, thefirst arm 222 of the first portion 150 is at least partially verticallyaligned with the second flex arm 220 of the second portion 152 to enablethe first arm 222 to deflect the second flex arm 220 as the firstportion is moved to the distal position.

The first arm 222 and the second arm 220 can be oriented distally suchthat at least a portion of the first arm 222 is located proximally overa protrusion (e.g., the ramp 224) of the second arm 220. This protrusioncan be configured to enable a collision between the first arm 222 andthe protrusion to cause the second arm 220 to deflect (to detach thebase 128 from the second portion 152).

In the embodiment illustrated in FIG. 18 , when the first portion 150 isin the proximal starting position, at least a section of the first arm222 is located directly over at least a portion of the second flex arm220 to enable the first arm 222 to deflect the second flex arm 220 asthe first portion 150 is moved to the distal position described above.The second flex arm 220 comprises a first horizontal protrusion (e.g.,the locking feature 232). The base 128 comprises a second horizontalprotrusion (e.g., the locking feature 230) latched with the firsthorizontal protrusion to couple the base 128 to the second portion 152of the telescoping assembly 132. The first arm 222 of the first portion150 deflects the second flex arm 220 of the second portion 152 tounlatch the base 128 from the second portion 152, which unlatches thebase 128 from the telescoping assembly 132.

Referring now to FIG. 7 , the system is configured to couple the glucosesensor 138 to the base 128 at a first position. The system is configuredto detach the base 128 from the telescoping assembly 132 at a secondposition that is distal relative to the first position.

A third flex arm (e.g., flex arm 202 in FIG. 15 ) couples the glucosesensor 138 to the base 128 at a first position. The second flex arm(e.g., flex arm 220 in FIG. 18 ) detaches from the base at a secondposition. The second position is distal relative to the first positionsuch that the system is configured to secure the base 128 to thetelescoping assembly 132 until after the glucose sensor 138 is securedto the base 128.

Spring Compression

Needles used in glucose sensor insertion applicators can be hazardous.For example, inadvertent needle-sticks can transfer diseases. Using aspring to retract the needle can reduce the risk of needle injuries.

Referring now to FIG. 7 , a spring 234 (e.g., a coil spring) can be usedto retract the needle hub 162 that supports the c-shaped needle 156. Theneedle hub 162 can be released at the bottom of insertion depth (toenable the needle 156 to retract). For example, when the needle 156reaches a maximum distal position, a latch 236 can release to enable thespring 234 to push the needle 156 proximally into a protective housing(e.g., into the first portion 150, which can be the protective housing).

Many applicators use pre-compressed springs. Many applicators usesubstantially uncompressed springs that are compressed by a user as theuser compresses the applicator. One disadvantage of a pre-compressedspring is that the spring force can cause the components to creep (e.g.,change shape over time), which can compromise the reliability of thedesign. One disadvantage of an uncompressed spring is that the first andsecond portions of the telescoping assembly can be free to move slightlyrelative to each other (when the assembly is in the proximal startingposition). This “chatter” of the first and second portions can make theassembly seem weak and flimsy.

Many of the components described herein can be molded from plastic(although springs are often metal). Preventing creep in plasticcomponents can help ensure that an applicator functions the same when itis manufactured and after a long period of time. One way to reduce thecreep risk is to not place the parts under a load (e.g., in storage)that is large enough to cause plastic deformation during a storage time.

Generating the retraction energy by storing energy in a spring duringdeployment limits the duration of load on the system. For example, theretraction force of the spring can be at least partially generated bycollapsing the telescoping assembly (rather storing the system with alarge retraction force of a fully pre-compressed spring).

Transcutaneous and implantable sensors are affected by the in vivoproperties and physiological responses in surrounding tissues. Forexample, a reduction in sensor accuracy following implantation of thesensor is one common phenomenon commonly observed. This phenomenon issometimes referred to as a “dip and recover” process. Dip and recover isbelieved to be triggered by trauma from insertion of the implantablesensor, and possibly from irritation of the nerve bundle near theimplantation area, resulting in the nerve bundle reducing blood flow tothe implantation area.

Alternatively, dip and recover may be related to damage to nearby bloodvessels, resulting in a vasospastic event. Any local cessation of bloodflow in the implantation area for a period of time leads to a reducedamount of glucose in the area of the sensor. During this time, thesensor has a reduced sensitivity and is unable to accurately trackglucose. Thus, dip and recover manifests as a suppressed glucose signal.The suppressed signal from dip and recover often appears within thefirst day after implantation of the signal, most commonly within thefirst 12 hours after implantation. Dip and recover normally resolveswithin 6-8 hours.

Identification of dip and recover can provide information to a patient,physician, or other user that the sensor is only temporarily affected bya short-term physiological response, and that there is no need to removethe implant as normal function will likely return within hours.

Minimizing the time the needle is in the body limits the opportunity fortissue trauma that can lead to phenomena such as dip and recover. Quickneedle retraction helps to limit the time the needle is in the body. Alarge spring retraction force can quickly retract the needle.

The embodiment illustrated in FIG. 7 solves the “chatter” problem,avoids substantial creep, and enables quick needle retraction. Theembodiment places the spring 234 in a slight preload between the firstportion 150 and the second portion 152 of the telescoping assembly 132.In other words, when the first portion 150 is in the proximal startingposition, the spring 234 is in a slightly compressed state due to therelaxed length of the spring 234 being longer than the length of thechamber in which the spring 234 resides inside the telescoping assembly132.

In some embodiments, the relaxed length of the spring 234 is at least 4percent longer than the length of the chamber. In several embodiments,the relaxed length of the spring 234 is at least 9 percent longer thanthe length of the chamber. In some embodiments, the relaxed length ofthe spring 234 is less than 18 percent longer than the length of thechamber. In several embodiments, the relaxed length of the spring 234 isless than 30 percent longer than the length of the chamber.

The spring 234 is compressed farther when the first portion 150 is moveddistally relative to the second portion 152. In some embodiments, thisslight preload has a much shorter compression length than thecompression length of typical fully pre-compressed springs. In severalembodiments, the preload causes a compression length of the spring 234that is less than 25 percent of the compression length of the fullycompressed spring 234. In some embodiments, the preload causes acompression length of the spring 234 that is greater than 3 percent ofthe compression length of the fully compressed spring 234. The slightpreload eliminates the “chatter” while having a force that is too smallto cause substantial creep of non-spring components in the system.

The spring 234 can be inserted into the first portion 150 via a hole 238in the proximal end of the first portion 150. Then, the needle hub 162(and the attached C-shaped needle 156) can be loaded through theproximal side of the first portion 150 of the telescoping assembly(e.g., via the hole 238 in the proximal end of the first portion 150).

The needle hub 162 is slid through the first portion 150 until radialsnaps (e.g., the release feature 160 of the needle hub 162) engage asection of the first portion 150 (see the latch 236). Thus, the spring234 is placed with a slight preload between the needle hub 162 and adistal portion of the first portion 150 of the telescoping assembly 132.

During applicator activation and the telescoping (e.g., collapsing ofthe first portion 150 into the second portion 152), the spring 234 iscompressed farther. At the bottom of travel (e.g., at the distal endingposition), the radial snaps of the needle hub 162 are forced radiallyinward by features (e.g., the protrusions 170) in the telescopingassembly 132 (as shown by the progression of FIGS. 7-11 ). This releasesthe needle hub 162 and allows the spring 234 to expand to drive theneedle 156 proximally out of the host (and into the first portion 150and/or the second portion 152).

As shown in FIG. 7 , the base 128 protrudes from the distal end of thesystem while the first portion 150 of the telescoping assembly 132 islocated in the proximal starting position and the glucose sensor 138 islocated remotely relative to the base 128. The glucose sensor 138 ismoveably coupled to the base 128 via the telescoping assembly 132because the glucose sensor 138 is coupled to the first portion 150 andthe base 128 is coupled to the second portion 152 of the telescopingassembly 132.

The system includes a spring 234 configured to retract a needle 156. Theneedle 156 is configured to facilitate inserting the glucose sensor 138into the skin. In some embodiments, the system does not include theneedle 156.

When the first portion 150 is in the proximal starting position, thespring 234 is in a first compressed state. The system is configured suchthat moving the first portion 150 distally from the proximal startingposition increases a compression of the spring 234. The first compressedstate places the first portion 150 and second portion 152 in tension.Latching features hold the first portion 150 and second portion 152 intension. In other words, in the proximal starting position, the latchingfeatures are configured to prevent the spring 234 from pushing the firstportion 150 proximally relative to the second portion 152. The latchingfeatures resist the first compressed state.

In several embodiments, the potential energy of the first compressedstate is less than the amount of potential energy necessary to retractthe needle 156. This low potential energy of the partiallypre-compressed spring 234 is typically insufficient to cause creep, yetis typically sufficient to eliminate the “chatter” described above.

Redundant systems can help ensure that the needle 156 (and in some casesthe sensor 138) can always be removed from the host after they areinserted into the host. If in extreme cases the necessary needle removalforce is greater than the spring retraction force, the user can pull theentire telescoping assembly 132 proximally to remove the needle 156and/or the sensor 138 from the host.

Some embodiments include a secondary retraction spring. In other words,in some embodiments, the spring 234 in FIG. 7 is actually two concentricsprings. (In several embodiments, the spring 234 is actually just onespring.) The secondary spring can be shorter than the primary retractionspring. The secondary retraction spring can provide additional needleretraction force and can enable additional tailoring of the forceprofile.

Many users desire to minimize the amount of material they throw away (astrash). Moving the needle 156 to the back of the applicator postdeployment enables easy access to remove the needle 156 post deployment.

FIG. 20 illustrates a perspective view of the needle 156, the needle hub162, and the spring 234 just after they were removed proximally from thehole 238 in a proximal end of the first portion 150 of the telescopingassembly 132.

The hole 238 is an opening at a proximal end of the applicator. The hole238 is configured to enable removing the needle 156, the needle hub 162,and/or the spring 234. This opening can be covered by a removable cover(e.g., a sticker, a hinged lid).

FIGS. 21 and 22 illustrate perspective views where a removable cover 272is coupled to the first portion 150 to cover the hole 238 through whichthe needle 156 can be removed from the telescoping assembly 132. A hinge274 can couple the cover 272 to the first portion 150 such that thecover 272 can rotate to close the hole 238 (as shown in FIG. 22 ) androtate to open the hole 238 (as shown in FIG. 21 ).

Removing the cover 272 can enable a user to remove the needle 156 fromthe applicator (e.g., the telescoping assembly 132) such that the usercan throw the needle 156 in a sharps container and reuse the applicatorwith a new needle. Removing the needle 156 from the applicator can alsoenable throwing the rest of the applicator into a normal trash collectorto reduce the amount of trash that needs to be held by the sharpscontainer.

The features described in the context of FIGS. 20-22 and 60 can becombined with any of the embodiments described herein.

FIG. 60 illustrates a perspective view of another telescoping assemblyembodiment 132 h. The cover 272 h is adhered to a proximal end of thetelescoping assembly 132 h to cover a hole configured to retrieve aneedle after the needle retracts (e.g., as described in the context ofFIGS. 21 and 22 ). Peeling the cover 272 h from the telescoping assembly132 h can enable a user to dump the needle 156 (shown in FIG. 7 ) into asharps container.

In this embodiment, the cover 272 h is a flexible membrane such as aTyvek label made by E. I. du Pont de Nemours and Company (“DuPont”). Thecover 272 h can include an adhesive to bond the cover 272 h to theproximal end of the telescoping assembly 132 h.

In some embodiments, a second cover 272 is adhered to a distal end ofthe telescoping assembly 132 h to cover the end of the telescopingassembly 132 h through which the sensor 138 (shown in FIG. 7 ) passes.The distal end of the telescoping assembly 132 h can also be covered bya plastic cap 122 h.

The cover 272 h can be configured to enable sterilization processes topass through the material of the cover 272 h to facilitate sterilizationof the interior of the telescoping assembly 132 h. For example,sterilization gases can pass through the cover 272 h.

Any of the features described in the context of FIG. 60 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIG. 60 can becombined with the embodiments described in the context of FIGS. 1-59 and61-70 .

The telescoping assembly 132 h can use the same interior features andcomponents as described in the context of FIG. 7 . One importantdifference is that the first portion 150 h slides on an outer surface ofthe second portion 152 (rather than sliding inside part of the secondportion 152 as shown in FIG. 7 ). Also, the telescoping assembly 132 hdoes not use a sterile barrier shell 120 (as shown in FIG. 2 ).

Any of the features described in the context of FIGS. 7-22 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 7-22 can becombined with the embodiments described in the context of FIGS. 23-70 .Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way, e.g., one, two, or three or more embodiments may be combinablein whole or in part. Further, any of the features of an embodiment maybe made optional to other aspects or embodiments. Any aspect orembodiment of a method can be performed by a system or apparatus ofanother aspect or embodiment, and any aspect or embodiment of a systemcan be configured to perform a method of another aspect or embodiment.

Force Profiles

Referring now to FIG. 7 , in some embodiments, moving the first portion150 of the telescoping assembly 132 distally relative to the secondportion 152 typically involves placing the distal end of the systemagainst the skin of the host and then applying a distal force on theproximal end of the system. This distal force can cause the firstportion 150 to move distally relative to the second portion 152 todeploy the needle 156 and/or the glucose sensor 138 into the skin.

The optimal user force generated axially in the direction of deploymentis a balance between preventing accidental premature deployment and easeof insertion. A force that is ideal at a certain portion of distalactuation may be far less than ideal at another portion of distalactuation.

The user places the applicator (e.g., the telescoping assembly 132)against the skin surface and applies a force distally on the applicator(e.g., by pushing down on the proximal end of the applicator). When theuser-generated force exceeds a threshold, the applicator collapses(e.g., telescopes distally) and the user drives the sensor into thebody.

Several embodiments include unique force profiles that reduce accidentalpremature deployment; dramatically increase the likelihood of completeand proper deployment; and reduce patient discomfort. Specificstructures enable these unique force profiles. For example, thefollowing structures can enable the unique force profiles describedherein: structures that hold the telescoping assembly 132 in theproximal starting position; structures that attach the sensor module 134to the base 128; structures that release the sensor module 134 from thefirst portion 150; structures that prevent the needle 156 fromretracting prematurely; structures that retract the needle 156;structures that release the base 128 from the second portion 152;structures that pad the collision at the distal position; and structuresthat hold the telescoping assembly 132 in a distal ending position.These structures are described in various sections herein.

Several embodiments include a system for applying an on-skin sensorassembly 600 to a skin 130 of a host (shown in FIG. 4 ). Referring nowto FIG. 7 , the system can comprise a telescoping assembly 132 having afirst portion 150 configured to move distally relative to a secondportion 152 from a proximal starting position to a distal position alonga path 154; a glucose sensor 138 coupled to the first portion 150; and alatch 236 configurable to impede a needle 156 from moving proximallyrelative to the first portion.

The first portion 150 is releasably secured in the proximal startingposition by a securing mechanism (e.g., the combination of 240 and 242in FIG. 7 ) that impedes moving the first portion 150 distally relativeto the second portion 152. The system is configured such that prior toreaching the distal position and/or by reaching the distal position,moving the first portion 150 distally relative to the second portion 152releases the latch 236 thereby causing the needle 156 to retractproximally into the system.

In several embodiments, the securing mechanism is formed by aninterference between the first portion 150 and the second portion 152.The interference can be configured to impede the first portion 150 frommoving distally relative to the second portion 152. For example, aradially outward protrusion 240 of the first portion 150 can collidewith a proximal end 242 of the second portion 152 such that moving thefirst portion 150 distally requires overcoming a force threshold tocause the first portion 150 and/or the second portion 152 to deform toenable the radially outward protrusion 240 to move distally relative tothe proximal end 242 of the second portion 152.

The system can include a first force profile measured along the path154. As shown in FIG. 23 , the force profile 244 can include force onthe Y axis and travel distance on the X axis. Referring now to FIGS. 7and 23 , the force profile 244 can be measured along the central axis196.

One way in which the force profile 244 can be measured is to place thetelescoping assembly 132 against the skin; place a force gauge such as aload cell on the proximal end of the telescoping assembly 132; calibratethe measurement system to account for the weight of the force gauge; andthen press on the proximal side of the force gauge to drive thetelescoping assembly 132 from the proximal starting position to thedistal position along the path 154. FIG. 23 illustrates force versusdistance from the proximal starting position based on this type oftesting procedure.

The first force profile 244 can comprise a first magnitude 246coinciding with overcoming the securing mechanism (e.g., 240 and 242), athird magnitude 250 coinciding with releasing the latch 236 (e.g.,releasing the needle retraction mechanism), and a second magnitude 248coinciding with an intermediate portion of the path 154 that is distalrelative to overcoming the securing mechanism and proximal relative toreleasing the latch 236.

In several embodiments, the second magnitude 248 is a peak forceassociated with compressing a needle retraction spring (e.g., the spring234 in FIG. 7 ) prior to beginning to release the latch 236. This peakforce can be at least 0.5 pounds, at least 1.5 pounds, less than 4pounds, and/or less than 6 pounds.

In several embodiments, the third magnitude 250 is a peak forceassociated with releasing the needle retraction mechanism. This peakforce can be at least 1 pound, at least 2 pounds, less than 4 pounds,and/or less than 6 pounds.

In some embodiments, the second magnitude 248 is less than the firstmagnitude 246 and the third magnitude 250 such that the system isconfigured to promote needle acceleration during the intermediateportion of the path 154 to enable a suitable needle speed at a time theneedle 156 (or the glucose sensor 138) first pierces the skin.

The first magnitude 246 can be the peak force required to overcome thesecuring mechanism (e.g., 240 and 242). This peak force can be at least5 pounds, at least 6 pounds, less than 10 pounds, and/or less than 12pounds. The first magnitude 246 can be at least 100 percent greater thanthe second magnitude 248. The first magnitude 246 can be at least 200percent greater than the second magnitude 248. The second magnitude 248can be during a portion of the force profile 244 where the compressionof the spring 234 is at least 50 percent of the maximum springcompression reached just before the needle 156 begins to retractproximally. The slope of the force profile 244 can be positive for atleast 1 millimeter during the time at which the second magnitude 248 ismeasured (due to the increasing spring force as the spring compressionincreases).

The first magnitude 246 can be greater than the third magnitude 250(and/or greater than the second magnitude 248) such that the system isconfigured to impede initiating a glucose sensor insertion cycle unlessa user is applying enough force to release the latch 236. For example,the force necessary for the protrusion 240 to move distally relative tothe proximal end 242 can deliberately be designed to be greater than theforce necessary to retract the needle 156.

To provide a sufficient safety margin, the first magnitude 246 can be atleast 50 percent greater than the third magnitude 250. In someembodiments, the first magnitude 246 is at least 75 percent greater thanthe third magnitude 250. To avoid a system where the first magnitude 246is unnecessarily high in light of the forces required along the path 154distally relative to the first magnitude 246, the first magnitude 246can be less than 250 percent greater than the third magnitude 250.

A second force profile 252 can coincide with the intermediate portion ofthe path 154. For example, the second magnitude 248 can be part of thesecond force profile 252. This second force profile 252 can include atime period in which the slope is positive for at least 1 millimeter, atleast 2.5 millimeters, less than 8 millimeters, and/or less than 15millimeters (due to the increasing spring force as the springcompression increases).

A proximal millimeter of the second force profile 252 comprises a loweraverage force than a distal millimeter of the second force profile 252in response to compressing a spring 234 configured to enable the systemto retract the needle 156 into the telescoping assembly 132.

The system also includes a first force profile 254 (measured along thepath 154). The first force profile 254 comprises a first averagemagnitude coinciding with moving distally past a proximal half of thesecuring mechanism and a second average magnitude coinciding with movingdistally past a distal half of the securing mechanism. The first averagemagnitude is greater than the second average magnitude such that thesystem is configured to impede initiating a glucose sensor insertioncycle unless a user is applying enough force to complete the glucosesensor insertion cycle.

A first force peak 256 coincides with moving distally past the proximalhalf of the securing mechanism. The first force peak 256 is at least 25percent higher than the second average magnitude.

The first force profile 254 comprises a first magnitude 246 coincidingwith overcoming the securing mechanism and a subsequent magnitudecoinciding with terminating the securing mechanism (e.g., moving pastthe distal portion of the securing mechanism). The first magnitude 246comprises a proximal vector and the subsequent magnitude comprises adistal vector. FIG. 23 is truncated at zero force, so the distal vectorappears to be have a magnitude of zero in FIG. 23 , although the actualvalue is negative (e.g., negative 2 pounds).

The proximal vector means the system is resisting the distal movement ofthe first portion 150 relative to the second portion 152. The distalvector means that the second half of the securing mechanism can helppropel the needle 156 and the sensor 138 towards the skin and/or intothe skin. In other words, the distal vector assists the distal movementof the first portion 150 relative to the second portion 152.

The third force profile 260 can include many peaks and values due to thefollowing events: the sensor module 134 docking to the base 128; thebase detaching from the second portion 152 (and thus detaching from thetelescoping assembly 132); the release feature 160 of the needle hub 162defecting inward due to the proximal protrusions 170 of the secondportion 152; the latch 236 releasing; the needle 156 retracting into aninner chamber of the first portion 150; and/or the first portion 150hits the distal position (e.g., the end of travel).

As shown in FIG. 7 , the securing mechanism can be a radially outwardprotrusion 240 (of the first portion 150) configured to collide with aproximal end 242 of the second portion 152 such that moving the firstportion 150 distally requires overcoming a force threshold to cause thefirst portion 150 and/or the second portion 152 to deform to enable theradially outward protrusion 240 to move distally relative to theproximal end 242 of the second portion 152. The radially outwardprotrusion 240 is configured to cause the second portion 152 to deformelliptically to enable the first portion 150 to move distally relativeto the second portion 152.

FIG. 24 illustrates another securing mechanism. At least a section ofthe first portion 150 interferes with a proximal end 242 of the secondportion 152 such that pushing the first portion 150 distally relative tothe second portion 152 requires a force greater than a force threshold.The force threshold is the minimum force necessary to deform at leastone of the first portion 150 and the second portion 152 to overcome theinterference 266, which is shown inside a dashed circle in FIG. 24 .

Many different interference geometries and types are used in variousembodiments. The interference can be between the first portion 150 andthe second portion 152. The interference can be between the needle hub162 and the second portion 152. For example, the interference can resistthe distal movement of the needle hub 162.

In some embodiments, the first portion 150 includes a taper 262. Once aninterfering section of the first portion 150 moves distally past theinterference area 266, the taper 262 makes the system such that theinterference 266 no longer impedes distal movement of the first portion150.

The second portion 152 can also have a taper 263. The taper 263 can beon an interior surface of the second portion 152 such that the interiorsize gets larger as measured proximally to distally along the taper 263.

The interfering portion 242 of the second portion 152 can include a ramp(as shown in FIG. 24 ) to aid the deformation described above. Theinterfering section of the first portion 150 is located proximallyrelative to the interfering section of the second portion 152.

The securing mechanism can comprise a radially outward protrusion (e.g.,240 in FIG. 7 ) of the first portion 150 that interferes with a radiallyinward protrusion of the second portion 152 (e.g., as shown by theinterference 266 in FIG. 24 ) such that the securing mechanism isconfigured to cause the second portion 152 to deform elliptically toenable the first portion 150 to move distally relative to the secondportion 152.

Any of the features described in the context of FIGS. 24-32 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 24-32 can becombined with the embodiments described in the context of FIGS. 1-23 and33-70 . Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way, e.g., one, two, or three or more embodiments may be combinablein whole or in part. Further, any of the features of an embodiment maybe made optional to other aspects or embodiments. Any aspect orembodiment of a method can be performed by a system or apparatus ofanother aspect or embodiment, and any aspect or embodiment of a systemcan be configured to perform a method of another aspect or embodiment.

FIG. 25 illustrates a cross sectional view of a portion of an embodimentin which the needle holder (e.g., the needle hub 162) is configured toresist distal movement of the first portion 150 relative to the secondportion 152 b. The second portion 152 b is like other second portions150 described herein (e.g., as shown in FIG. 7 ) except that the secondportion 152 b includes flex arms 276 that are at least part of thesecuring mechanism. The flex arms 276 are releasably coupled to theneedle holder to releasably secure the first portion 150 to the secondportion 152 b in the proximal starting position (as shown in FIG. 7 ).

The needle 156 (shown in FIG. 7 ) is retractably coupled to the firstportion 150 by the needle holder 162. The needle holder 162 isconfigured to resist distal movement of the first portion 150 relativeto the second portion 152 b due to a chamfer and/or a ramp 278interfering with flex arms 276. Pushing the first portion 150 distallyrequires overcoming the force necessary to deflect the flex arms 276outward such that the flex arms 276 move out of the way of the ramp 278.

FIG. 27 illustrates a perspective view of another securing mechanism, afrangible release 280. FIG. 26 illustrates a top view of a frangiblering 282. The ring 282 includes two frangible tabs 284 that protruderadially inward. In some embodiments, the tabs 284 are radially inwardprotrusions on opposite sides of the ring 282 relative to each other.The frangible member (e.g., the ring 282) can be part of the firstportion 150, the second portion 152, or any other portion of the system.For example, the frangible member can be a feature of a molded secondportion 152.

The ring 282 can be made of a brittle material configured to enable thetabs 284 to break when the first portion 150 is pushed distally relativeto the second portion 152. For example, a section of the first portion150 can be located proximally over the tab 284 when the first portion150 is in the proximal starting position (as shown in FIG. 27 by thefrangible release 280). Moving the first portion 150 distally can causethe section of the first portion 150 to bend and/or break the tab 284.

In some embodiments, a radially outward protrusion 286 of the firstportion 150 is configured to bend and/or break the tab 284. The ring282, the tab 284, and the other components described herein can bemolded from a plastic such as acrylonitrile butadiene styrene,polyethylene, and polyether ether ketone. (Springs, interconnects, andneedles can be made of steel.) In some embodiments, the ring 282 is atleast 0.2 millimeters thick, at least 0.3 millimeters thick, less than0.9 millimeters thick, and/or less than 1.5 millimeters thick.

The ring 282 can be secured between the first portion 150 and the secondportion 152 of the telescoping assembly 132. The ring 282 can wraparound a perimeter of the first portion 150 and can be locatedproximally relative to the second portion 152 such that the ring 282rests against a proximal end of the second portion 152.

The ring 282 enables a frangible coupling between the first portion 150and the second portion 152 while the first portion 150 is in theproximal starting position. In FIG. 27 , the system is configured suchthat moving the first portion 150 to the distal position breaks thefrangible coupling (e.g., the frangible release 280).

In some embodiments, the tabs 284 are not part of a ring 282. The tabs284 can be part of the second portion 152 or part of the first portion150.

FIG. 27 also includes a magnet system 290. The magnet system 290includes a magnet and a metal element in close enough proximity that themagnet is attracted to the metal element (e.g., a metal disk). Forexample, the second portion 152 can include a magnet, and the firstportion 150 can include the metal element. In several embodiments, thesecond portion 152 can include a metal element, and the first portion150 can include the magnet.

The magnet and metal element can be located such that they are locatedalong a straight line oriented radially outward from the central axis196 (shown in FIG. 7 ). This configuration can position the magnet forsufficient attraction to the metal element to resist movement of thefirst portion 150. For example, when the first portion 150 is in theproximal starting position, the magnetic force of the magnet system 290can resist distal movement of the first portion. Thus, the magnetreleasably couples the first portion 150 to the second portion 152 whilethe first portion 150 is in the proximal starting position.

In several embodiments, a user can compress an internal spring or thespring can be pre-compressed (e.g., compressed fully at the factory).The telescoping assembly can include a button 291 configured to releasethe spring force to cause the needle and/or the sensor to move into theskin.

The cover 272 h described in the context of FIG. 60 can be adhered tothe proximal end of the first portion 150 shown in FIG. 27 . The cover272 h can be used with any of the embodiments described herein.

FIG. 31 illustrates a side view of a telescoping assembly 132 e having afirst portion 150 e and a second portion 152 e. The first portion 150 eincludes a radially outward protrusion 286 e configured to engage aradially inward ramp 296 located on an interior wall of the secondportion 152 e. When a user applies a distal, axial force on the firstportion 150 e, the protrusion 286 e collides with the ramp 296. Theangle of the ramp causes the first portion 150 e to rotate relative tothe second portion 152 e. This rotation resists the distal force andacts as a securing mechanism. Once the protrusion 286 e moves beyond thedistal end of the ramp 296, the ramp 296 no longer causes rotation, andthus, no longer acts as a securing mechanism.

Many of the embodiments described herein rely on a compressive force ofa person. Many unique structures enable the force profiles describedherein. The structures help ensure the compressive force caused by aperson pushing distally on a portion of the system results in reliableperformance. One challenge of relying on people to push downward on thesystem to generation appropriate forces is that the input force can varysubstantially by user. Even a single user can apply different inputforces on different occasions.

One solution to this variability is to replace the need for auser-generated input force with a motor-generated force. The motor canprovide reliable input forces. Motors also enable varying the force atdifferent sections of the path from the proximal starting position tothe distal position.

FIGS. 28-30 illustrates embodiments of telescoping assemblies 132 c, 132d that include motors 290 c, 290 d to drive a needle 156 and/or aglucose sensor 138 into the skin. The motors 290 c, 290 d can be linearactuators that use an internal magnetic system to push a rod distallyand proximally. The linear actuators can also convert a rotary inputinto linear motion to push a rod distally and proximally. The movementof the rod can move various portions of the system including the needle156, the needle hub 162 c, the first portion 150 c, 150 d of thetelescoping assembly 132 c, 132 d, the sensor module 134, and/or thesensor 138. The motors 290 c, 290 d can include internal batteries tosupply electricity for the motors 290 c, 290 d.

FIG. 28 illustrates a perspective, cross-sectional view of an embodimentin which the motor 290 c pushes the needle hub 162 c distally relativeto the motor 290 c and relative to the second portion 152 c. The needlehub 162 c can include a rod that slides in and out of the housing of themotor 292 c. The distal movement of the needle hub 162 c can push atleast a portion of the needle 156 and/or the sensor 138 (shown in FIG. 7) into the skin. The distal movement of the needle hub 162 c can movethe sensor module 134 distally such that the sensor module 134 dockswith the base 128. This coupling can precede the detachment of the base128 from the telescoping assembly 132 c.

FIGS. 29 and 30 illustrate side, cross-sectional views of another motorembodiment. In this embodiment, the rod 294 of the motor 292 d iscoupled to and immobile relative to the second portion 152 d of thetelescoping assembly 132 d. The motor 292 d is coupled to and immobilerelative to the first portion 150 d of the telescoping assembly 132 d.As a result, pulling the rod 294 into the housing of the motor 292 dcauses the first portion 150 d to move distally relative to the secondportion 152 d. The glucose module 134 is coupled to a distal portion ofthe first portion 150 d (as described herein). Thus, the glucose sensor138 is moved distally into the skin of the host and the glucose module134 is coupled to the base 128. As illustrated in FIGS. 29 and 30 , theembodiment does not include a needle. Similar embodiments can include aneedle.

FIG. 32 illustrates a perspective, cross-section view of the telescopingassembly 132. In some embodiments, a protrusion 302 of the first portion150 couples with a hole 304 of the second portion 152. The protrusion302 can be oriented distally to latch with the hole 304 in response tothe first portion 150 reaching the distal position.

In several embodiments, a protrusion 302 of the second portion 152couples with a hole 304 of the first portion 150. The protrusion 302 canbe oriented proximally to latch with the hole 304 in response to thefirst portion 150 reaching the distal position.

The protrusion 302 can be a flex arm that is at least 10 millimeterslong, at least 15 millimeters long, and/or less than 50 millimeterslong. The protrusion 302 can include an end portion that protrudes at anangle relative to the central axis of the majority of the protrusion302. This angle can be at least 45 degrees, at least 75 degrees, lessthan 110 degrees, and/or less than 135 degrees.

Coupling the protrusion 302 to the hole 304 can permanently lock thefirst portion 150 in a downward position (that is distal to the proximalstarting position and is within 3 millimeter of the distal position)while the needle 156 is in a retracted state. This locking can preventthe system from being reused and can prevent needle-stick injuries.

Any of the features described in the context of FIG. 23 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIG. 23 can becombined with the embodiments described in the context of FIGS. 1-22 and24-70 . Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way, e.g., one, two, or three or more embodiments may be combinablein whole or in part. Further, any of the features of an embodiment maybe made optional to other aspects or embodiments. Any aspect orembodiment of a method can be performed by a system or apparatus ofanother aspect or embodiment, and any aspect or embodiment of a systemcan be configured to perform a method of another aspect or embodiment.

Interconnects

Referring now to FIG. 4 , in many embodiments, the electronic unit 500drives a voltage bias through the sensor 138 so that current can bemeasured. Thus, the system is able to analyze glucose levels in thehost. The reliability of the electrical connection between the sensor138 and the electronics unit 500 is critical for accurate sensor datameasurement.

In many embodiments, the host or a caregiver create the electricalconnection between the sensor 138 and the electronics unit 500. A seal192 can prevent fluid ingress as the electronics unit 500 is pressedonto the glucose sensor module 134. Oxidation and corrosion can changeelectrical resistance of the system and are sources of error and noisein the signal.

The electrical connections should be mechanically stable. Relativemovement between the parts of the electrical system can cause signalnoise, which can hinder obtaining accurate glucose data.

A low-resistance electrical connection is more power efficient. Powerefficiency can help maximize the battery life of the electronics unit500.

In embodiments where the host or caregiver must compress the electricalinterconnect and/or seal 192, minimizing the necessary force increaseuser satisfaction. Lowering the user-applied force makes the transmittereasier to install. If the necessary force is too great, users andcaregivers may inadvertently fail to apply adequate force, which canjeopardize the reliability and performance of the system. The force thatthe user needs to apply to couple the electronics unit 500 to the base128 and sensor module 134 is strongly influenced by the force necessaryto compress the interconnect. Thus, there is a need for an electricalinterconnect with a lower compression force.

Manufacturing variability, host movement, and temperature variationswhile the host is using the on-skin sensor assembly 600 necessitateproviding a robust electrical connection throughout an activecompression range (which encompasses the minimum and maximum compressionstates reasonably possible). Thus, there is a need for electricalconnections that are tolerant of compression variation within the activecompression range.

Metallic springs (e.g., coil or leaf springs) can be compressed betweenthe sensor 138 and the electronics unit 500 to provide a robust,reliable electrical connection that requires a low compression force tocouple the electronics unit 500 to the base 128.

FIG. 33 illustrates a perspective view of an on-skin senor assembly justbefore the electronics unit 500 (e.g., a transmitter) is snapped ontothe base 128. Coupling the electronics unit 500 to the base 128 cancompress the seal 192 to prevent fluid ingress and can compress aninterconnect (e.g., springs 306) to create an electrical connection 310between the glucose sensor 138 and the electronics unit 500.

Creating the electrical connection 310 and/or coupling the electronicsunit 500 to the base 128 can cause the electronics unit 500 (e.g., atransmitter) to exit a sleep mode. For example, conductive members(e.g., of the sensor module 134 and/or of the base 128) can touchelectrical contacts of the electronics unit 500 (e.g., electricalcontacts of a battery of the electronics unit 500), which can cause theelectronics unit 500 to exit a sleep mode. The conductive member of thesensor module 134 and/or of the base 128 can be a battery jumper thatcloses a circuit to enable electricity from the battery to flow intoother portions of the electronics unit 500.

Thus, creating the electrical connection 310 and/or coupling theelectronics unit 500 to the base 128 can “activate” the electronics unit500 to enable and/or to prepare the electronics unit 500 to wirelesslytransmit information to other devices 110-113 (shown in FIG. 1 ). U.S.Patent Publication No. US-2012-0078071-A1 includes additionalinformation regarding transmitter activation. The entire contents ofU.S. Patent Publication No. US-2012-0078071-A1 are incorporated byreference herein.

The distal face of the electronics unit 500 can include planarelectrical contacts that touch the proximal end portions of the springs306. The distal end portions of the springs 306 can contact variousconductive elements of the glucose sensor 138. Thus, the springs 306 canelectrically couple the electronics unit 500 to the various conductiveelements of the glucose sensor 138. In the illustrated embodiment, twometallic springs 306 electrically connect the glucose sensor 138 and theelectronics unit 500. Some embodiments use one spring 306. Otherembodiments use three, four, five, ten, or more springs 306.

Metallic springs 306 (e.g., gold-plated springs) are placed above thesensor wire 138 in the sensor module 134. The sensor 138 is locatedbetween a rigid polymer base 128 and the bottom surface of the spring306. The top surface of the spring 306 contacts a palladium electrodelocated in the bottom of the electronics module 500. The rigidelectronics module 500 and the rigid polymer base 128 are broughttogether creating a compressed sandwich with the sensor 138 and thespring 306.

The springs 306 can be oriented such that their central axes are within25 degrees of the central axis 196 of the telescoping assembly 132(shown in FIG. 7 ). The springs 306 can have a helical shape. Thesprings 306 can be coil springs or leaf springs.

Springs 306 can have ends that are plain, ground, squared, squared andground, or any other suitable configuration. Gold, copper, titanium, andbronze can be used to make the springs 306. Springs 306 can be made fromspring steel. In several embodiments, the steels used to make thesprings 306 can be low-alloy, medium-carbon steel or high-carbon steelwith a very high yield strength. The springs 306 can be compressionsprings, torsion springs, constant springs, variable springs, helicalsprings, flat springs, machined springs, cantilever springs, volutesprings, balance springs, leaf springs, V-springs, and/or washersprings.

Some embodiments use a spring-loaded pin system. The spring system caninclude a receptacle. A pin can be located partially inside thereceptacle such that the pin can slide partially in and out of thereceptacle. A spring can be located inside the receptacle such that thespring biases the pin outward towards the electronics unit 500. Thereceptacle can be electrically coupled to the sensor 138 such thatpressing the electronics unit 500 onto the spring-loaded pin systemelectrically couples the electronics unit 500 and the sensor 138.

Mill-Max Mfg. Corp. of Oyster Bay, N.Y., U.S.A. (“Mill-Max”) makes aspring-loaded pin system with a brass-alloy shell that is plated withgold over nickel. One Mill-Max spring-loaded pin system has a stainlesssteel spring and an ordering code of 0926-1-15-20-75-14-11-0.

In several embodiments, the electronics unit 500 includes a battery toprovide electrical power to various electrical components (e.g., atransmitter) of the electronics unit 500.

In some embodiments, the base 128 can include a battery 314 that islocated outside of the electronics unit 500. The battery 314 can beelectrically coupled to the electrical connection 310 such that couplingthe electronics unit 500 to the base 128 couples the battery 314 to theelectronics unit 500. FIGS. 22B and 22C of U.S. Patent Publication No.US-2009-0076360-A1 illustrate a battery 444, which in some embodiments,can be part of the base (which can have many forms including the form ofbase 128 shown in FIG. 33 herein). The entire contents of U.S. PatentPublication No. US-2009-0076360-A1 are incorporated by reference herein.

FIG. 34 illustrates a perspective view of the sensor module 134.Protrusions 308 can secure the springs 306 to the sensor module 134.(Not all the protrusions 308 are labeled in order to increase theclarity of FIG. 34 .) The protrusions 308 can protrude distally.

At least three, at least four, and/or less than ten protrusions 308 canbe configured to contact a perimeter of a spring 306. The protrusions308 can be separated by gaps. The gaps enable the protrusions 308 toflex outward as the spring 306 is inserted between the protrusions 308.The downward force of coupling the electronics unit 500 to the base 128can push the spring 306 against the sensor 138 to electrically couplethe spring 306 to the sensor 138. The sensor 138 can run between atleast two of the protrusions 308.

FIG. 33 illustrates an on-skin sensor system 600 configured fortranscutaneous glucose monitoring of a host. The on-skin sensor system600 can be used with the other components shown in FIG. 7 . The sensormodule 134 can be replaced with the sensor modules 134 d, 134 e shown inFIGS. 35 and 37 . Thus, the sensor modules 134 d, 134 e shown in FIGS.35 and 37 can be used with the other components shown in FIG. 7 .

Referring now to FIGS. 33 and 34 , the system 600 can include a sensormodule housing 312; a glucose sensor 138 a, 138 b having a first section138 a configured for subcutaneous sensing and a second section 138 bmechanically coupled to the sensor module housing 312; and an electricalinterconnect (e.g., the springs 306) mechanically coupled to the sensormodule housing 312 and electrically coupled to the glucose sensor 138 a,138 b. The springs can be conical springs, helical springs, or any othertype of spring mentioned herein or suitable for electrical connections.

The sensor module housing 312 comprises at least two proximalprotrusions 308 located around a perimeter of the spring 306. Theproximal protrusions 308 are configured to help orient the spring 306. Asegment of the glucose sensor 138 b is located between the proximalprotrusions 308 (distally to the spring 306).

The sensor module housing 312 is mechanically coupled to the base 128.The base 128 includes an adhesive 126 configured to couple the base 128to skin of the host.

The proximal protrusions 308 orient the spring 306 such that coupling anelectronics unit 500 to the base 128 presses the spring 306 against afirst electrical contact of the electronics 500 unit and a secondelectrical contact of the glucose sensor 138 b to electrically couplethe glucose sensor 138 a, 138 b to the electronics unit 500.

Referring now to FIGS. 33 and 35-38 , the system 600 can include asensor module housing 312 d, 312 e; a glucose sensor 138 a, 138 b havinga first section 138 a configured for subcutaneous sensing and a secondsection 138 b mechanically coupled to the sensor module housing 312 d,312 e; and an electrical interconnect (e.g., the leaf springs 306 d, 306e) mechanically coupled to the sensor module housing 312 d, 312 e andelectrically coupled to the glucose sensor 138 a, 138 b. The sensormodules 134 d, 134 e can be used in place of the sensor module 134 shownin FIG. 7 . The leaf springs 306 d, 306 e can be configured to bend inresponse to the electronics unit 500 coupling with the base 128.

As used herein, cantilever springs are a type of leaf spring. As usedherein, a leaf spring can be made of a number of strips of curved metalthat are held together one above the other. As used herein in manyembodiments, leaf springs only include one strip (e.g., one layer) ofcurved metal (rather than multiple layers of curved metal). For example,the leaf spring 306 d in FIG. 35 can be made of one layer of metal ormultiple layers of metal. In some embodiments, leaf springs include onelayer of flat metal secured at one end (such that the leaf spring is acantilever spring).

As shown in FIGS. 35 and 36 , the sensor module housing 312 d comprisesa proximal protrusion 320 d having a channel 322 d in which at least aportion of the second section of the glucose sensor 138 b is located.The channel 322 d positions a first area of the glucose sensor 138 bsuch that the area is electrically coupled to the leaf spring 306 d.

As shown in the cross-sectional, perspective view of FIG. 36 , the leafspring 306 d arcs away from the first area and protrudes proximally toelectrically couple with an electronics unit 500 (shown in FIG. 33 ). Atleast a portion of the leaf spring 306 d forms a “W” shape. At least aportion of the leaf spring 306 d forms a “C” shape. The leaf spring 306d bends around the proximal protrusion 320 d. The leaf spring 306 dprotrudes proximally to electrically couple with an electronics unit 500(shown in FIG. 33 ). The seal 192 is configured to impede fluid ingressto the leaf spring 306 d.

The leaf spring 306 d is oriented such that coupling an electronics unit500 to the base 128 (shown in FIG. 33 ) presses the leaf spring 306 dagainst a first electrical contact of the electronics unit 500 and asecond electrical contact of the glucose sensor 138 b to electricallycouple the glucose sensor 138 a, 138 b to the electronics unit 500. Theproximal height of the seal 192 is greater than a proximal height of theleaf spring 306 d such that the electronics unit 500 contacts the seal192 prior to contacting the leaf spring 306 d.

Referring now to FIGS. 33 and 37-38 , the sensor module housing 312 ecomprises a channel 322 e in which at least a portion of the secondsection of the glucose sensor 138 b is located. A distal portion of theleaf spring 306 e is located in the channel 322 e such that a proximalportion of the leaf spring 306 e protrudes proximally out the channel322 e.

The sensor module housing 312 e comprises a groove 326 e that cutsacross the channel 322 e (e.g., intersects with the channel 322 e). Theleaf spring 306 e comprises a tab 328 located in the groove to impederotation of the leaf spring. At least a portion of the leaf spring 306 eforms a “C” shape.

FIGS. 36 and 38 illustrate two leaf spring shapes. Other embodiments useother types of leaf springs. Elements shown in FIGS. 33-38 can becombined.

Referring now to FIGS. 33-38 , interconnects 306, 306 d, 306 e cancomprise a palladium contact, an alloy, a clad material, an electricallyconductive plated material, gold plated portions, silver material,and/or any suitable conductor. Interconnects 306, 306 d, 306 e describedherein can have a resistance of less than 5 ohms, less than 20 ohms,and/or less than 100 ohms. Many interconnect embodiments enable aresistance of approximately 2.7 ohms or less, which can significantlyincrease battery life compared to higher resistance alternatives.

Reducing the force necessary to compress an interconnect 306, 306 d, 306e (e.g., as an electronics unit 500 is coupled to the base 128) canreduce coupling errors and difficulties. For example, if the necessaryforce is high, odds are substantial that users will inadvertently failto securely couple the electronics unit 500 to the base 128. In somecases, if the necessary force is too high, some users will be unable tocouple the electronics unit 500 to the base 128. Thus, there is a needfor systems that require less force to couple the electronics unit 500to the base 128.

Many embodiments described herein (e.g., spring embodiments)dramatically reduce the force necessary to couple the electronics unit500 to the base 128. The interconnects 306, 306 d, 306 e can have acompression force of at least 0.05 pounds; less than 0.5 pounds, lessthan 1 pound, less than 3 pounds; and/or less than 4.5 pounds over anactive compression range.

In some embodiments, the interconnects 306, 306 d, 306 e may require acompression force of less than one pound to compress the spring 20percent from a relaxed position, which is a substantially uncompressedposition. In some embodiments, the interconnects 306, 306 d, 306 e mayrequire a compression force of less than one pound to compress thespring 25 percent from a relaxed position, which is a substantiallyuncompressed position. In some embodiments, the interconnects 306, 306d, 306 e may require a compression force of less than one pound tocompress the spring 30 percent from a relaxed position, which is asubstantially uncompressed position. In some embodiments, theinterconnects 306, 306 d, 306 e change dependency to independent claim)may require a compression force of less than one pound to compress thespring 50 percent from a relaxed position, which is a substantiallyuncompressed position.

Springs 306, 306 d, 306 e can have a height of 2.6 millimeters, at least0.5 millimeters, and/or less than 4 millimeters. The seal 192 can have aheight of 2.0 millimeters, at least 1 millimeter, and/or less than 3millimeters. In some embodiments, in their relaxed state (i.e., asubstantially uncompressed state), springs 306, 306 d, 306 e protrude(e.g., distally) at least 0.2 millimeters and/or less than 1.2millimeters from the top of the seal 192.

When the electronics unit 500 is coupled to the base 128, thecompression of the springs 306, 306 d, 306 e can be 0.62 millimeters, atleast 0.2 millimeters, less than 1 millimeter, and/or less than 2millimeters with a percent compression of 24 percent, at least 10percent, and/or less than 50 percent. Active compression range of thesprings 306, 306 d, 306 e can be 16 to 40 percent, 8 to 32 percent, 40to 57 percent, 29 to 47 percent, at least 5 percent, at least 10percent, and/or less than 66 percent.

In some embodiments, the electrical connection between the sensor 138and the electronics unit 500 is created at the factory. This electricalconnection can be sealed at the factory to prevent fluid ingress, whichcan jeopardize the integrity of the electrical connection.

The electrical connection can be made via any of the followingapproaches: An electrode can pierce a conductive elastomer (such thatvertical deformation is not necessary); the sensor can be “sandwiched”(e.g., compressed) between adjacent coils of a coil spring; conductiveepoxy; brazing; laser welding; and resistance welding.

Referring now to FIGS. 4, 6, 7, and 33 , one key electrical connectionis between the electronics unit 500 (e.g., a transmitter) and the sensormodule 134. Another key electrical connection is between the sensormodule 134 and the glucose sensor 138. Both connections should be robustto enable connecting the sensor module 134 to the base 128, and thenconnecting the base 128 and sensor module 134 to the electronics unit500 (e.g., a transmitter). A stable sensor module 134 allows the sensormodule 134 to couple to the base 128 without causing signal noise in thefuture.

These two key electrical connections can be made at the factory (e.g.,prior to the host or caregiver receiving the system). These electricalconnections can also be made by the host or caregiver when the userattaches the electronics unit 500 to the base 128 and/or the sensormodule 134.

In some embodiments, the connection between the glucose sensor 138 andthe sensor module 134 can be made at the factory (e.g., prior to theuser receiving the system), and then the user can couple the electronicsunit 500 to the sensor module 134 and/or the base 128. In severalembodiments, the electronics unit 500 can be coupled to the sensormodule 134 and/or to the base 128 at the factory (e.g., prior to theuser receiving the system), and then the user can couple this assemblyto the glucose sensor 138.

Any of the features described in the context of FIGS. 33-38 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 33-38 can becombined with the embodiments described in the context of FIGS. 1-32 and39-70 . Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way, e.g., one, two, or three or more embodiments may be combinablein whole or in part. Further, any of the features of an embodiment maybe made optional to other aspects or embodiments. Any aspect orembodiment of a method can be performed by a system or apparatus ofanother aspect or embodiment, and any aspect or embodiment of a systemcan be configured to perform a method of another aspect or embodiment.

Referring now to FIG. 33 , the battery 314 can be located inside theelectronics unit 500 or can be part of the base 128. Maximizing the lifeof the battery 314 is important to many reasons. For example, theelectronics unit 500 may be in storage for months or even years beforeit is used. If the battery 413 is substantially depleted during thisstorage, the number of days that a host can use the electronics unit(e.g., to measure an analyte) can be dramatically diminished.

In some embodiments, the electronics unit 500 is in alow-power-consumption state (e.g., a “sleep” mode) during storage (e.g.,prior to being received by the host). This low-power-consumption statecan drain the battery 314. Thus, there is a need for a system thatreduces or even eliminates battery power consumption during storageand/or prior to the electronics unit 500 being coupled to the base 128.

As described in the context of FIG. 33 , creating the electricalconnection 310 and/or coupling the electronics unit 500 to the base 128can cause the electronics unit 500 (e.g., a transmitter) to exit a sleepmode. For example, conductive members (e.g., of the sensor module 134and/or of the base 128) can touch electrical contacts of the electronicsunit 500 (e.g., electrical contacts of a battery of the electronics unit500), which can cause the electronics unit 500 to exit a sleep modeand/or can begin the flow of electrical power from the battery. Theconductive member of the sensor module 134 and/or of the base 128 can bea battery jumper that closes a circuit to enable electricity from thebattery to flow into other portions of the electronics unit 500.

Thus, creating the electrical connection 310 and/or coupling theelectronics unit 500 to the base 128 can “activate” the electronics unit500 to enable and/or to prepare the electronics unit 500 to wirelesslytransmit information to other devices 110-113 (shown in FIG. 1 ). U.S.Patent Publication No. US-2012-0078071-A1 includes additionalinformation regarding electronics unit 500 activation (e.g., transmitteractivation). The entire contents of U.S. Patent Publication No.US-2012-0078071-A1 are incorporated by reference herein.

FIG. 65 illustrates a perspective view of portions of a sensor module134 j. Some items, such as springs and sensors, are hidden in FIG. 65 toclarify that the sensor module 134 j can use any spring or sensordescribed herein. The sensor module 134 j can use any of the springs306, 306 d, 306 e; sensors 138, 138 a, 138 b; protrusions 308; channels322 d, 322 e; and grooves 326 e described herein (e.g., as shown inFIGS. 34-40 ). The sensor module 134 j can be used in the place of anyother sensor module described herein. The sensor module 134 j can beused in the embodiment described in the context of FIG. 7 and can beused with any of the telescoping assemblies described herein.

FIG. 66 illustrates a cross-sectional side view of the sensor moduleshown in FIG. 65 . Referring now to FIGS. 65-70 , the sensor module 134j includes a conductive jumper 420 f (e.g., a conductive connection thatcan comprise metal). The conductive jumper 420 f is configured toelectrically couple two electrical contacts 428 a, 428 b of theelectronics unit 500 (e.g., a transmitter) in response to coupling theelectronics unit 500 to the sensor module 134 j and/or to the base 128.

The conductive jumper 420 f can be located at least partially betweentwo electrical connections 426 (e.g., springs 306, 306 d, 306 e shown inFIGS. 34-38 ). The conductive jumper 306 f can include two springs 306 fcoupled by a conductive link 422 f A first spring 306 f of the jumper420 f can be coupled to a first contact 428 a, and a second spring 306 fof the jumper 420 f can be coupled to a second contact 428 b, which cancomplete an electrical circuit to enable the battery to provideelectricity to the electronics unit 500. The springs 306 f can be leafsprings, coil springs, conical springs, and/or any other suitable typeof spring. In some embodiments, the springs 306 f are proximalprotrusions that are coupled with the contacts 428 a, 428 b.

As shown in FIG. 66 , the conductive link 422 f can be arched such thata sensor 138 b (shown in FIG. 34 ) passes under and/or through thearched portion of the conductive link 422 f. In several embodiments, theconductive link 422 f is oriented within plus or minus 35 degrees ofperpendicular to the sensor 138 b such that the conductive link 422 fcrosses over the portion of the sensor 138 b that is located inside theseal area (e.g., within the interior of the seal 192).

FIG. 67 illustrates a perspective view of portions of a sensor module134 k that is similar to the sensor module 134 j shown in FIGS. 65 and66 . FIG. 68 illustrates a top view of the sensor module 134 k shown inFIG. 67 .

Referring now to FIGS. 67 and 68 , the sensor module 134 k includes adifferent type of conductive jumper 420 g, which includes two helicalsprings 306 g conductively coupled by a conductive link 422 g. Theconductive link 422 g is configured to cross over or under the sensor138 b (shown in FIG. 34 ). As shown in FIGS. 67 and 68 , the springs 306g are conical springs, however, some embodiments do not use conicalsprings. The springs 306 g are configured to electrically couple twoelectrical contacts 428 a, 428 b of the electronics unit 500 to startthe flow the electricity within the electronics unit 500. Thus, theconductive jumper 420 g can “activate” the electronics unit 500. Theconductive jumper 420 g can be used with any of the sensor modulesdescribed herein.

FIGS. 69 and 70 illustrate perspective views of an electronics unit 500just before the electronics unit 500 is coupled to a base 128. As shownin FIG. 70 , the electronics unit 500 can have two electrical contacts428 a, 428 b configured to be electrically coupled to a conductivejumper 420 f (shown in FIGS. 65 and 66 ), 420 g (shown in FIGS. 67 and68 ). The electronics unit 500 can also have two electrical contacts 428c, 428 d configured to be electrically coupled to the springs 306, 306d, 306 e (shown in FIGS. 34-38 ) and/or to any other type of electricalconnection 426 between the sensor 138 (shown in FIG. 39 ) and theelectronics unit 500.

Coupling the electronics unit 500 to the sensor module 134 k and/or tothe base 128 can electrically and/or mechanically couple the electricalcontacts 428 a, 428 b to the conductive jumper 420 f (shown in FIG. 65), 420 g (shown in FIG. 67 ).

Coupling the electronics unit 500 to the sensor module 134 k and/or tothe base 128 can electrically and/or mechanically couple the electricalcontacts 428 c, 428 d to the springs 306, 306 d, 306 e (shown in FIGS.34-38 ) and/or to any other type of electrical connection 426 (e.g., asshown in FIG. 67 ) between the sensor 138 (shown in FIG. 39 ) and theelectronics unit 500.

Any of the features described in the context of FIGS. 65-70 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 65-70 can becombined with the embodiments described in the context of FIGS. 1-64 .Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way, e.g., one, two, or three or more embodiments may be combinablein whole or in part. Further, any of the features of an embodiment maybe made optional to other aspects or embodiments. Any aspect orembodiment of a method can be performed by a system or apparatus ofanother aspect or embodiment, and any aspect or embodiment of a systemcan be configured to perform a method of another aspect or embodiment.

Needle Angle and Off Set

FIG. 43 shows a front view of a “C-shaped” needle 156. FIG. 42illustrates a bottom view of the C-shaped needle 156. The needle 156includes a channel 330. A section 138 a (shown in FIG. 34 ) of theglucose sensor 138 (labeled in FIG. 7 ) that is configured forsubcutaneous sensing can be placed in the channel 330 (as shown in FIG.40 ).

The needle 156 can guide the sensor 138 into the skin of the host. Adistal portion of the sensor 138 can be located in the channel 330 ofthe needle 156. Sometimes, a distal end of the sensor 138 sticks out ofthe needle 156 and gets caught on tissue of the host as the sensor 138and needle 156 are inserted into the host. As a result, the sensor 138may buckle and fail to be inserted deeply enough into the subcutaneoustissue. In other words, in some embodiments, the sensor wire must beplaced within the channel 330 of the C-shaped needle 156 to be guidedinto the tissue and must be retained in the channel 330 duringdeployment.

The risk of the sensor 138 sticking out of the channel 330 (and therebyfailing to be property inserted into the host) can be greatly diminishedby placing the sensor 138 in the channel 330 of the needle 156 with aparticular angle 338 (shown in FIG. 41 ) and offset 336 (shown in FIG.40 . Position B 334 in FIG. 42 illustrates a sensor sticking out of thechannel 330.

The angle 338 and offset 336 cause elastic deformation of the sensor 138to create a force that pushes the sensor 138 to the bottom of thechannel 300 (as shown by position A 332 in FIG. 42 ) while avoidingpotentially detrimental effects of improper angles 338 and offset 336.The angle 338 and offset 336 can also cause plastic deformation of thesensor 138 to help shape the sensor 138 in a way that minimizes the riskof the sensor 138 being dislodged from the channel 330 during insertioninto the skin.

In several embodiments, the angle 338 and offset 336 shape portions ofthe sensor 138 for optimal insertion performance. For example, the angle338 can bend the sensor 138 prior to placing portions of the sensor 138in the channel 330 of the needle 156.

As illustrated in FIG. 39 , a portion of the glucose sensor 138 b (alsolabeled in FIG. 34 ) can be placed in a distally facing channel 342(which, in some embodiments, is a tunnel). This channel 342 can helporient the glucose sensor 138 b towards the channel 330 of the needle156 (shown in FIG. 43 ).

As illustrated in FIG. 41 , the glucose sensor 138 can include an angle338 between a portion of the glucose sensor 138 that is coupled to thesensor module housing 312 (shown in FIG. 34 ) and a portion of theglucose sensor that is configured to be inserted into the host. In someembodiments, this angle 338 can be formed prior to coupling the sensor138 to the sensor module house 312 (shown in FIG. 34 ) and/or prior toplacing a portion of the sensor 138 in the channel 330 of the needle 156(shown in FIG. 43 ).

Referring now to FIG. 41 , an angle 338 that is less than 110 degreescan result in deployment failures (e.g., with an offset of 0.06 inchesplus 0.06 inches and/or minus 0.03 inches). In some embodiments, anangle 338 that is less than 125 degrees can result in deploymentfailures (e.g., with an offset of 0.06 inches plus 0.06 inches and/orminus 0.03 inches). An angle 338 of 145 degrees (plus 5 degrees and/orminus 10 degrees) can reduce the probability of deployment failures. Insome embodiments, the angle 338 is at least 120 degrees and/or less than155 degrees.

In some embodiments, a manufacturing method includes bending the sensor138 prior to placing portions of the sensor 138 in the channel 330 ofthe needle 156. In this manufacturing method, an angle is measured froma central axis of a portion of the glucose sensor 138 that is coupled tothe sensor module housing 312 (shown in FIG. 34 ) and a portion of theglucose sensor that is configured to be inserted into the needle.According to this angle measurement, an angle that is greater than 70degrees can result in deployment failures (e.g., with an offset of 0.06inches plus 0.06 inches and/or minus 0.03 inches). In some embodiments,an angle that is greater than 55 degrees can result in deploymentfailures (e.g., with an offset of 0.06 inches plus 0.06 inches and/orminus 0.03 inches). An angle of 35 degrees (plus 10 degrees and/or minus5 degrees) can reduce the probability of deployment failures. In someembodiments, the angle is at least 25 degrees and/or less than 60degrees.

An offset 336 (shown in FIG. 40 ) that is too large can result in thesensor 138 not being reliably held in the channel 330 (shown in FIG. 42). In other words, a large offset 336 can result in the sensor 138 beinglocated in position B 334 rather than securely in position A 332. Anoffset 336 that is too small can place too much stress on the sensor138, which can break the sensor 138. In light of these factors, inseveral embodiments, the offset 336 is at least 0.02 inches, at least0.04 inches, less than 0.08 inches, and/or less than 0.13 inches. Insome embodiments, the offset 336 is equal to or greater than 0.06 inchesand/or less than or equal to 0.10 inches. The offset 336 is measured asshown in FIG. 40 from the root of the needle 156.

In some embodiments, at least a portion of the bend of the sensor 138can include a strain relief. For example, the bend of the sensor 138 canbe encapsulated in a polymeric tube or an elastomeric tube to providestrain relief for the sensor 138. In some instances, the entire bend ofthe sensor 138 can be encapsulated in a polymeric tube or an elastomerictube. In some embodiments, the tube is composed of a soft polymer. Thepolymeric tube or elastomeric tube can encapsulate the sensor 138 by aheat shrink process. In some embodiments, a silicone gel may be appliedto the sensor at or near channel 342 (shown in FIG. 39 ), or along atleast a portion of the underside of proximal protrusion 320 d (shown inFIG. 35 ).

The needle channel width 344 (shown in FIG. 42 ) can be 0.012 inches. Insome embodiments, the width 344 is equal to or greater than 0.010 inchesand/or less than or equal to 0.015 inches. The width 344 of the channel330 is measured at the narrowest span in which the glucose sensor 138could be located.

Referring now to FIG. 40 , a funnel 182 in the base 128 can help guidethe needle 156 and/or the glucose sensor 138 into the hole 180. Thefunnel 182 and the hole 180 can help secure the sensor 138 in theC-shaped needle 156 during storage and deployment. For example, the hole180 can be so small that there is not extra room (within the hole 180)for the sensor 138 to exit the channel 330 (shown in FIG. 42 ) of theneedle 156.

Another role of the funnel 182 and hole 180 is to support the needle 156and/or the sensor 138 against buckling forces during insertion of theneedle 156 and/or the sensor 138 into the host.

The funnel 182 and the hole 180 also protect against inadvertentneedle-stick injuries (because they are too small to enable, forexample, a finger to reach the needle 156 prior to needle deployment).

The sensor module 134 is unable to pass through the funnel 182 and hole180 (e.g., due to the geometries of the sensor module 134 and the funnel182). Preventing the sensor module 134 from passing through the base 128ensures the sensor module 134 is removed from the host's body when thebase 128 is detached from the host. The angle 338 can prevent all of thesensor 138 from passing through the hole 180 to ensure the sensor 138 isremoved from the host's body when the base 128 is detached from thehost.

Any of the features described in the context of FIGS. 39-43 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 39-43 can becombined with the embodiments described in the context of FIGS. 1-38 and44-70 . Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way, e.g., one, two, or three or more embodiments may be combinablein whole or in part. Further, any of the features of an embodiment maybe made optional to other aspects or embodiments. Any aspect orembodiment of a method can be performed by a system or apparatus ofanother aspect or embodiment, and any aspect or embodiment of a systemcan be configured to perform a method of another aspect or embodiment.

Needle-Free

Some embodiments use a needle to help insert a glucose sensor intosubcutaneous tissue. Some people, however, are fearful of needles. Inaddition, needle disposal can require using a sharps container, whichmay not be readily available.

Many embodiments do not use a needle to insert the sensor, which canhelp people feel more comfortable inserting the sensor and can eliminatethe need to use a sharps container to dispose of the applicator orportions thereof.

U.S. Patent Publication No. US-2011-0077490-A1, U.S. Patent PublicationNo. US-2014-0107450-A1, and U.S. Patent Publication No.US-2014-0213866-A1 describe several needle-free embodiments. The entirecontents of U.S. Patent Publication No. US-2011-0077490-A1, U.S. PatentPublication No. US-2014-0107450-A1, and U.S. Patent Publication No.US-2014-0213866-A1 are incorporated by reference herein.

Any of the embodiments described herein can be used with or without aneedle. For example, the embodiments described in the context of FIGS.1-50 can be used with or without a needle. For example, the embodimentshown in FIG. 7 can be used in a very similar way without the needle156. In this needle-free embodiment, moving the first portion 150distally drives a distal portion of the glucose sensor 138 into the skin(without the use of a needle 156). In needle-free embodiments, thesensor 138 can have sufficient buckling resistance such that (whensupported by the hole 180) the sensor 138 does not buckle. Sharpening adistal tip of the sensor 138 can also facilitate needle-free insertioninto the host.

FIG. 56 illustrates an embodiment very similar to the embodiment shownin FIG. 7 except that the embodiment of FIG. 56 does not include aneedle. The telescoping assembly 132 b pushes the sensor 138 (which canbe any type of analyte sensor) into the body of the host. The embodimentshown in FIG. 56 does not include a needle hub 162, a spring 234, or aneedle retraction mechanism 158 (as shown in FIG. 7 ) but can includeany of the items and features described in the context of otherembodiments herein.

FIG. 57 illustrates the first portion 150 moving distally relative tothe second portion 152 of the telescoping assembly 132 b to move thesensor module 134 and the sensor 138 towards the base 128 in preparationto couple the sensor module 134 and the sensor 138 to the base 128.

FIG. 58 illustrates the first portion 150 in a distal ending positionrelative to the second portion 152. The sensor module 134 and the sensor138 are coupled to the base 128. The base 128 is no longer coupled tothe telescoping assembly 132 b such that the telescoping assembly 132 bcan be discarded while leaving the adhesive 126 coupled to the skin ofthe host (as described in the context of FIGS. 4-6 ).

The embodiment illustrated in FIGS. 56-58 can be integrated into theapplicator system 104 shown in FIGS. 2 and 3 .

The items and features described in the context of FIGS. 12A-50 can alsobe used with the embodiment illustrated in FIGS. 56-58 . Items andfeatures are described in the context of certain embodiments to reduceredundancy. The items and features shown in all the drawings, however,can be combined. The embodiments described herein have been designed toillustrate the interchangeability of the items and features describedherein.

FIGS. 44 and 45 illustrate another embodiment of a telescoping assembly132 g. This embodiment includes a first portion 150 g that movesdistally relative to a second portion 152 g to push a glucose sensor 138g through a hole in a base 128 g and into a host.

The first portion 150 g (e.g., a pusher) of the telescoping assembly 132g can include a distal protrusion 352 that supports a substantiallyhorizontal section of the glucose sensor 138 g (e.g., as the glucosesensor 138 g protrudes out from the sensor module 134 g). The end of thedistal protrusion 352 can include a groove 354 in which at least aportion of the glucose sensor 138 g is located. The groove 354 can helpretain the glucose sensor 138 g. The distal protrusion 352 can provideaxial support to the glucose sensor 138 g (e.g., to push the glucosesensor 138 g distally into the tissue of the host).

The base 128 g can include a funnel 182 g that faces proximally to helpguide a distal end of the glucose sensor 138 g into a hole 180 g in thebase 128 g. The hole 180 g can radially support the sensor 138 g as thesensor 138 g is inserted into the tissue of the host.

When the first portion 150 g of the telescoping assembly 132 g is in theproximal starting position, the distal end of the glucose sensor 138 gcan be located in the hole 180 g to help guide the glucose sensor 138 gin the proper distal direction.

The hole 180 g can exit a convex distal protrusion 174 g in the base 128g. The convex distal protrusion 174 g can help tension the skin prior tosensor insertion. As described more fully in other embodiments, the base128 g can rest against the skin of the host as the sensor module 134 gmoves distally towards the base 128 g and then is coupled to the base128 g.

The telescoping assembly 132 g (e.g., an applicator) does not include aneedle. As a result, there is no sharp in the applicator, whicheliminates any need for post-use sharp protection. This design traitprecludes a need for a retraction spring or needle hub. The distal endof the sensor wire 138 g can be sharpened to a point to mitigate a needfor an insertion needle.

The telescoping assembly 132 g (e.g., an applicator) can include thefirst portion 150 g and the second portion 152 g. The base 128 g can becoupled to a distal end of the first portion 150 g. The glucose sensor138 g and the sensor module 134 g can be coupled to a distal end of thefirst portion 150 g such that he applicator does not require a spring,needle, or needle hub; the first portion 150 g is secured in a proximalstarting position by an interference between the first portion 150 g andthe second portion 152 g of the telescoping assembly 132 g; and/orapplying a distal force that is greater than a breakaway threshold ofthe interference causes the first portion 150 g to move distallyrelative to the second portion 152 g (e.g., until the sensor 138 g isinserted into the tissue and the sensor module 134 g is coupled to thebase 128 g).

FIGS. 46 and 47 illustrate a similar needle-free embodiment. Thisembodiment does not use the distal protrusion 352 shown in FIG. 45 .Instead, the sensor module 134 h includes a distally oriented channel358 that directs the sensor 138 h distally such that the glucose sensor138 h includes a bend that is at least 45 degrees and/or less than 135degrees. A channel cover 362 secures the glucose sensor 138 h in thedistally oriented channel 358.

The embodiments illustrated in FIGS. 44-47 can be integrated into theapplicator system 104 shown in FIGS. 2 and 3 . Referring now to FIG. 2 ,the electronics unit 500 (e.g., a transmitter having a battery) can bedetachably coupled to the sterile barrier shell 120. The rest of theapplicator system 104 can be sterilized, and then the electronics unit500 can be coupled to the sterile barrier shell 120 (such that theelectronics unit 500 is not sterilized with the rest of the applicatorsystem 104).

The items and features described in the context of FIGS. 12A-43 and48-70 can also be used with the embodiments illustrated in FIGS. 44-47 .Items and features are described in the context of certain embodimentsto reduce redundancy. The items and features shown in all the drawings,however, can be combined. The embodiments described herein have beendesigned to illustrate the interchangeability of the items and featuresdescribed herein.

Any of the features described in the context of FIGS. 44-47 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 44-47 can becombined with the embodiments described in the context of FIGS. 1-43 and48-70 . Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way, e.g., one, two, or three or more embodiments may be combinablein whole or in part. Further, any of the features of an embodiment maybe made optional to other aspects or embodiments. Any aspect orembodiment of a method can be performed by a system or apparatus ofanother aspect or embodiment, and any aspect or embodiment of a systemcan be configured to perform a method of another aspect or embodiment.

In some embodiments, the sensor 138 can be deployed (e.g., into the skinof the host) in response to coupling the electronics unit 500 (e.g., atransmitter) to the base 128. The sensor 138 can be any type of analytesensor (e.g., a glucose sensor).

Premature deployment of the sensor 138 can cause insertion of the sensor138 into the wrong person and/or insufficient sensor insertion depth.Premature deployment can also damage the sensor 138, which in someembodiments, can be fragile. Thus, there is a need to reduce thelikelihood of premature sensor deployment.

One way to reduce the likelihood of premature sensor deployment is forthe system to include an initial resistance (e.g., to coupling theelectronics unit 500 to the base 128). The initial resistance cannecessitate a force buildup prior to overcoming the initial resistance.When the initial resistance is overcome, the sensor 138 is typicallydeployed faster than would be the case without an initial resistance(e.g., due to the force buildup, which can be at least 0.5 pounds, 1pound, and/or less than 5 pounds). This fast deployment can reduce painassociated with the sensor insertion process.

In some embodiments, the resistance to coupling the electronics unit 500to the base 128 after overcoming the initial resistance is less than 10percent of the initial resistance, less than 40 percent of the initialresistance, and/or at least 5 percent of the initial resistance. Havinga low resistance to coupling the electronics unit 500 to the base 128after overcoming the initial resistance can enable fast sensorinsertion, which can reduce the pain associated with the sensorinsertion process.

FIGS. 56-58 illustrate the first portion 150 deploying the sensor 138into the skin of the host. In some embodiments, the first portion 150 isreplaced with the electronics unit 500 shown in FIG. 4 such thatcoupling the electronics unit 500 to the base 128 pushes the sensor 138into the skin of the host. Referring now to FIGS. 4 and 56-58 , theprotrusion 240 (as explained in other embodiments) can be a portion ofthe electronics unit 500 such that moving the electronics unit distallyrelative to the second portion 152 and/or coupling the electronics unit500 to the base 128 requires overcoming the initial resistance of theprotrusion 240.

In some embodiments configured such that the sensor 138 is deployed(e.g., into the skin of the host) in response to coupling theelectronics unit 500 to the base 128, a telescoping assembly 132 b isnot used. Instead, features of the base 128 provide the initialresistance to coupling the electronics unit 500 to the base 128.Although the locking feature 230 in FIG. 33 is used for differentpurposes in some other embodiments, the locking feature 230 of the base128 can couple with a corresponding feature of the electronics unit 500.This coupling can require overcoming an initial resistance.

Any of the features and embodiments described in the context of FIGS.1-70 can be applicable to all aspects and embodiments in which thesensor 138 is deployed (e.g., into the skin of the host) in response tocoupling the electronics unit 500 (e.g., a transmitter) to the base 128.

Vertical Locking

After a telescoping assembly (e.g., an applicator) has been used toinsert a glucose sensor, the needle used to insert the glucose sensorcould inadvertently penetrate another person. To guard against thisrisk, the telescoping assembly can protect people from subsequentneedle-stick injuries by preventing the first portion of the telescopingassembly from moving distally relative to the second portion after thesensor has been inserted into the host.

FIG. 48 illustrates a perspective, cross-sectional view of a telescopingassembly 132 i that includes a first portion 150 i and a second portion152 i. Referring now to FIGS. 48-50 , the first portion 150 i isconfigured to telescope distally relative to the second portion 152 i.The second portion 152 i of the telescoping assembly 132 i can include aproximal protrusion 364 that can slide past a lock-out feature 366 ofthe first portion 150 i of the telescoping assembly 132 i as the firstportion 150 i is moved distally.

The proximal protrusion 364 can be biased such that elastic deformationof the proximal protrusion 364 creates a force configured to press theproximal protrusion 364 into the bottom of the lock-out feature 366 oncethe proximal protrusion 364 engages the lock-out feature 366.

The proximal protrusion 364 does not catch on the lock-out feature 366as the first portion 150 i moves distally a first time. Once the firstportion 150 i is in a distal ending position, a spring can push thefirst portion 150 i to a second proximal position. Rather than returningto the starting proximal position, the proximal protrusion 364 catcheson the lock-out feature 366 (due to the bias of the proximal protrusion364 and the distally facing notch 368 of the lock-out feature 366).

Once a proximal end of the proximal protrusion 364 is captured in thelock-out feature 366, the rigidity of the proximal protrusion 364prevents the first portion 150 i of the telescoping assembly 132 i frommoving distally a second time.

As the first portion 150 i moves distally relative to the second portion152 i, a ramp 370 of the first portion 150 i pushes the proximalprotrusion 364 outward (towards the lock-out feature 366). The proximalprotrusion 364 can be located between two distal protrusions 372 of thefirst portion 150 i. The distal protrusions 372 can guide the proximalprotrusion 364 along the ramp 370.

As a portion of the proximal protrusion 364 slides along the ramp 370(as the first portion 150 i moves distally), the ramp bends the proximalprotrusion 364 until a portion of the proximal protrusion 364 that waspreviously between the two distal protrusions 372 is no longer betweenthe distal protrusions 372. Once the portion of the proximal protrusion364 is no longer between the two distal protrusions 372, the proximalprotrusion 364 is in a state to catch on the notch 368. The notch 368can be part of the distal protrusions 372.

The second portion 152 i of the telescoping assembly 132 i can include aproximal protrusion 364, which can be oriented at an angle between zeroand 45 degrees relative to a central axis). The first portion 150 i ofthe telescoping assembly 132 i can include features that cause theproximal protrusion 364 to follow a first path as the first portion 150i moves distally and then to follow a second path as the first portion150 i moves proximally. The second path includes a locking feature 366that prevents the first portion 150 i from moving distally a secondtime.

The first portion 150 i can include a ramp 370 that guides the proximalprotrusion 364 along the first path. A distal protrusion (e.g., the ramp370) of the first portion 150 i can bias the proximal protrusion 364 tocause the proximal protrusion 364 to enter the second path as the firstportion 150 i moves proximally. The proximal protrusion 364 can be aflex arm. The lock 366 can comprise a distally facing notch 368 thatcatches on a proximal end of the proximal protrusion 364.

As shown in FIGS. 48 and 50 , the telescoping assembly 132 i can includea sensor module 134 i. The sensor module 134 i can be any of the sensormodules described herein.

Any of the features described in the context of FIGS. 48-50 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 48-50 can becombined with the embodiments described in the context of FIGS. 1-47 and51-70 . Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way, e.g., one, two, or three or more embodiments may be combinablein whole or in part. Further, any of the features of an embodiment maybe made optional to other aspects or embodiments. Any aspect orembodiment of a method can be performed by a system or apparatus ofanother aspect or embodiment, and any aspect or embodiment of a systemcan be configured to perform a method of another aspect or embodiment.

Dual-Spring Assembly

Partial sensor insertion can lead to suboptimal sensing. In some cases,partial sensor insertion can create a needle-stick hazard (due to theneedle not retracting into a protective housing). Thus, there is a needfor systems that ensure full sensor insertion.

The embodiment illustrated in FIGS. 61-64 dramatically reduces the oddsof partial sensor insertion by precluding sensor insertion untilsufficient potential energy is stored in the system. The potentialenergy is stored in a first spring 402.

The system includes many items from the embodiment illustrated in FIG. 7(e.g., the base 128 and the sensor module 134). The system includes anoptional needle 156 and needle hub 162. The embodiment illustrated inFIGS. 61-64 can also be configured to be needle-free by removing theneedle 156, the second spring 234, the needle hub 162, and the needleretraction mechanism 158.

The telescoping assembly 132 k has three portions 150 k, 152 k, 392.Moving the third portion 392 distally relative to the second portion 152k stores energy in the first spring 402 (by compressing the first spring402). Once the first portion 150 k is unlocked from the second portion152 k, the energy stored in the compressed first spring 402 is used topush the first portion 150 k distally relative to the second portion 152k to drive the sensor 138 (shown in FIG. 7 ) into the skin of the host.

To ensure the first portion 150 k does not move distally relative to thesecond portion 152 k until the first spring 402 is sufficientlycompressed (and thus has enough stored energy), the first portion 150 kis locked to the second portion 152 k. Once the first spring 402 issufficiently compressed (and thus has enough stored energy), the systemunlocks the first portion 150 k from the second portion 152 k to enablethe stored energy to move the sensor 138 (and in some embodiments theneedle 156) into the skin of the host.

The telescoping assembly 132 k can lock the third portion 392 to thesecond portion 152 k in response to the third portion 392 reaching asufficiently distal position relative to the second portion 152 k. Aprotrusion 408 can couple with a hole 410 to lock the third portion 392to the second portion 152 k.

Some embodiments do not include locking protrusion 408 and do not lockthe third portion 392 to the second portion 152 k in response to thethird portion 392 reaching a sufficiently distal position relative tothe second portion 152 k.

In several embodiments, sufficiently distal positions are at least 3millimeters, at least 5 millimeters, and/or less than 30 millimetersdistal relative to the proximal starting position.

The telescoping assembly 132 k can lock the first portion 150 k to thesecond portion 152 k in response to the first portion 150 k reaching asufficiently distal position relative to the second portion 152 k. Aprotrusion 412 (e.g., a distal protrusion) can couple with a hole 414(e.g., in a surface that is within plus or minus 30 degrees ofperpendicular to the central axis of the telescoping assembly 132 k) tolock the first portion 150 k to the second portion 152 k.

Some embodiments include a needle 156 to help insert a sensor into skinof a host. In embodiments that include a needle 156, the telescopingassembly 132 k can include the needle retraction mechanism 158 describedin the context of FIG. 7 . Moving the first portion 150 k to asufficiently distal position relative to the second portion 152 k cantrigger the needle retraction mechanism 158 (e.g., can release a latch)to enable a second spring 234 to retract the needle 156.

FIG. 61 illustrates a system for applying an on-skin sensor assembly 600(shown in FIGS. 4-6 ) to a skin of a host. The system comprises atelescoping assembly 132 k having a first portion 150 k configured tomove distally relative to a second portion 152 k from a proximalstarting position (e.g., the position shown in FIG. 61 ) to a distalposition (e.g., the position shown in FIG. 64 ) along a path; a sensor138 (shown in FIG. 64 ) coupled to the first portion 150 k; and a base128 comprising adhesive 126 configured to couple the sensor 138 to theskin. The telescoping assembly 132 k can further comprise a thirdportion 392 configured to move distally relative to the second portion152 k.

In some embodiments, the first portion 150 k is located inside of thesecond portion 152 k such that the second portion 152 k wraps around thefirst portion 150 k in a cross section taken perpendicularly to thecentral axis of the telescoping assembly 132 k.

In some embodiments, a first spring 402 is positioned between the thirdportion 392 and the second portion 152 k such that moving the thirdportion 392 distally relative to the second portion 152 k compresses thefirst spring 402. The first spring 402 can be a metal helical springand/or a metal conical spring. In several embodiments, the first spring402 is a feature molded as part of the third portion 392, as part of thesecond portion 152 k, or as part of the first portion 150 k. The firstspring 402 can be molded plastic.

The telescoping assembly 132 k can be configured such that the firstspring 402 is not compressed in the proximal starting position and/ornot compressed during storage. In several embodiments, the telescopingassembly 132 k can be configured such that the first spring 402 is notcompressed more than 15 percent in the proximal starting position and/orduring storage (e.g., to avoid detrimental spring relaxation and/orcreep of other components such as at least one of the third portion 392,the second portion 152 k, and the first portion 150 k).

Some embodiments that include a needle 156 do not include a needle hub162. In these embodiments, the second spring 234 can be located betweenthe second portion 152 k and the first portion 150 k such that movingthe first portion 150 k distally relative to the second portion 152 kcompresses the second spring 234 to enable the second spring 234 to pushthe first portion 150 k proximally relative to the second portion 152 kto retract the needle 156 (e.g., after sensor insertion).

In several embodiments, the second spring 234 is compressed while thetelescoping assembly 132 k is in the proximal starting position. Forexample, the second spring 234 can be compressed at the factory whilethe telescoping assembly 132 k is being assembled such that when theuser receives the telescoping assembly 132 k, the second spring 234 isalready compressed (e.g., compressed enough to retract the needle 156).

The second spring 234 can have any of the attributes and featuresassociated with the spring 234 described in the context of otherembodiments herein (e.g., in the context of the embodiment of FIG. 7 ).

In some embodiments, the movement of the sensor module 134 (e.g., ananalyte sensor module) and the sensor 138 (e.g., an analyte sensor)relative to the base 128 can be as described in the context of otherembodiments (e.g., as shown by the progression illustrated by FIGS. 7-11).

In the proximal starting position of the telescoping assembly 132 k, thefirst portion 150 k can be locked to the second portion 152 k. Thesystem can be configured such that moving the third portion 392 distallyrelative to the second portion 152 k unlocks the first portion 150 kfrom the second portion 152 k.

In several embodiments, a first proximal protrusion 394 having a firsthook 396 passes through a first hole 398 in the second portion 152 k tolock the first portion 150 k to the second portion 152 k. The thirdportion 392 can comprise a first distal protrusion 404. The system canbe configured such that moving the third portion 392 distally relativeto the second portion 152 k engages a ramp 406 to bend the firstproximal protrusion 394 to unlock the first portion 150 k from thesecond portion 152 k.

In some embodiments, the sensor 138 is located within the second portion152 k while the base 128 protrudes from the distal end of the systemsuch that the system is configured to couple the sensor 138 to the base128 by moving the first portion 150 k distally relative to the secondportion 152 k.

In several embodiments, a sensor module 134 is coupled to a distalportion of the first portion 150 k such that moving the first portion150 k to the distal position couples the sensor module 134 to the base128. This coupling can be as described in the context of otherembodiments herein. The sensor 138 can be coupled to the sensor module134 while the first portion 150 k is located in the proximal startingposition.

The system can be configured such that the third portion 392 movesdistally relative to the second portion 152 k before the first spring402 moves the first portion 150 k distally relative to the secondportion 152 k. The system can be configured such that moving the thirdportion 392 distally relative to the second portion 152 k unlocks thefirst portion 150 k from the second portion 150 k and locks the thirdportion 392 to the second portion 152 k.

A first protrusion 408 couples with a hole 410 of at least one of thesecond portion 152 k and the third portion 392 to lock the third portion392 to the second portion 152 k.

In some embodiments, the system comprises a second protrusion 412 thatcouples with a hole 414 of at least one of the first portion 150 k andthe second portion 152 k to lock the first portion 150 k to the secondportion 152 k in response to moving the first portion 150 k distallyrelative to the second portion 152 k.

In several embodiments, a first spring 402 is positioned between thethird portion 392 and the second portion 152 k such that moving thethird portion 392 distally relative to the second portion 152 kcompresses the first spring 402 and unlocks the first portion 150 k fromthe second portion 152 k, which enables the compressed first spring 402to push the first portion 150 k distally relative to the second portion152 k, which pushes at least a portion of the sensor 138 out of thedistal end of the system and triggers a needle retraction mechanism 158to enable a second spring 234 to retract a needle 156.

In yet another aspect, disclosed herein is a dual spring-based sensorinsertion device having a pre-connected sensor assembly (i.e. an analytesensor electrically coupled to at least one electrical contact beforesensor deployment). Such a sensor insertion device provides convenientand reliable insertion of a sensor into a user's skin by a needle aswell as reliable retraction of a needle after the sensor is inserted,which are features that provide convenience to users as well aspredictability and reliability of the insertion mechanism. Thereliability and convenience of a dual spring based sensor insertiondevice having an automatic insertion and automatic retraction provide isa significant advancement in the field of sensor insertion devices.Furthermore, such a device can provide both safety and shelf stability.

In several embodiments, the insertion device can include a first springand a second spring. In such embodiments, either or both of the firstspring and the second spring can be integrally formed with portions of atelescoping assembly, such as the first portion and the second portionof a telescoping assembly. In several embodiments, either or both of thefirst spring and the second spring can be formed separately from andoperatively coupled to portions of the telescoping assembly. Forexample, in some embodiments, the insertion spring can be integrallyformed with a portion of the telescoping assembly while the retractionspring is a separate part which is operatively coupled to a portion ofthe telescoping assembly.

In some embodiments, rather than being configured to undergo compressionduring energization, either or both of the first spring and the secondspring can be configured to undergo tensioning during energization. Inthese embodiments, the couplings between the springs and the portions ofthe telescoping assembly, as well as the couplings between the movingportions of the assembly (for example in the resting state, and duringactivation, deployment, and retraction) can be adjusted to drive and/orfacilitate the desired actions and reactions within the system. Forexample, in an embodiment employing a tensioned retraction spring todrive the insertion process, the retraction spring can be coupled to orintegrally formed with the second portion of the telescoping assembly.In such an embodiment, the retraction spring can be pre-tensioned in theresting state. In other such embodiments, the retraction spring can beuntensioned in the resting state, and tensioned during the sensorinsertion process.

In several embodiments, either or both of the first spring and thesecond spring can be substantially unenergized and/or unstressed whenthe system is in a resting state. In several embodiments, either or bothof the first spring and the second spring can be energized and/orstressed when the system is in a resting state. As used herein, the term“energized” means that enough potential energy is stored in the springto perform the desired actions and reactions within the system. In someembodiments, the first spring can be partly energized in the restingstate, such that the user can supply a lesser amount of force to fullyenergize the first spring. In some embodiments, the second spring can bepartly energized in the resting state, such that the energy stored inthe first spring (either in the resting state or after energization by auser) can provide force to energize the second spring. In someembodiments, the energy stored in the first spring can providesufficient force to energize the second spring to at least retract theneedle from the skin. In some embodiments, either or both of the firstspring and the second spring can be compressed or tensioned by 50% ormore, 60% or more, 70% or more, 80% or more, 90% or more, or 100% in theresting state. In other embodiments, either or both of the first springand the second spring can be compressed or tensioned by 50% or less, 40%or less, 30% or less, 20% or less, 15% or less, 10% or less, 5% or less,or 0% in the resting state.

In embodiments in which both the first spring and the second spring aresubstantially unenergized in the resting state, they can be stressed bythe same amounts, similar amounts, or entirely different amounts. Inembodiments in which both the first spring and the second spring areeffectively energized in the resting state, they can be stressed by thesame amounts, similar amounts, or entirely different amounts. Inembodiments in which the second spring is substantially unenergized inthe resting state, the first spring can be configured to store enoughenergy to drive both the desired movement in the system (e.g., themovement of the first portion in a distal direction), as well as theenergization of the second spring.

With reference now to FIGS. 71-75 , another embodiment of a system 104 mfor applying an on-skin sensor assembly to skin of a host isillustrated. The embodiment illustrated in FIGS. 71-75 may reduce thepotential of incomplete sensor insertion by precluding sensor insertionuntil sufficient potential energy is stored in the system. The potentialenergy for inserting the sensor can be stored in an actuator, such as afirst spring 402 m. The embodiment may provide other advantages such ascontrolled speed, controlled force, and improved user experience.

The system 104 m may include many features from the embodimentillustrated in FIG. 7 (e.g., the needle 156, the base 128 and the sensormodule 134). The system 104 m may include alternative elements, such as,but not limited to, a needle hub 162 m, a second spring 234 m, and aneedle retraction mechanism 158 m. The embodiment illustrated in FIGS.71-75 can also be configured to be needle-free by removing the needle156, the second spring 234 m, the needle hub 162 m, and the needleretraction mechanism 158 m. In such embodiments, the sensor may be aself-insertable sensor.

The system 104 m may include many features that are similar to those ofthe embodiment illustrated in FIGS. 61-64 (e.g., a telescoping assembly132 m) including a first portion 150 m, a second portion 152 m, and athird portion 392 m; with locking features 396 m and 398 m configured toreleasably lock the first portion 150 m to the second portion 152 muntil the third portion 392 m has reached a sufficiently distal positionrelative to the second portion 152 m to compress the first spring 402 mand store enough energy in the spring 402 m to drive insertion of thesensor 138 (and in some embodiments the needle 156) into the skin of ahost; locking features 408 m and 410 m configured to lock the thirdportion 392 m to the second portion 152 m (e.g., to prevent proximalmovement of the third portion 392 m relative to the second portion 152m) in response to the third portion 392 m reaching a sufficiently distalposition relative to the second portion 152 m; unlocking features 404 mand 406 m configured to unlock the locking features 396 m and 398 m atleast after the third portion 392 m is locked to the second portion 152m and/or the first spring 402 m is sufficiently compressed; lockingfeatures 412 m and 414 m configured to lock the first portion 150 m tothe second portion 152 m in response to the first portion 150 m reachinga sufficiently distal position relative to the second portion 152 m todrive the sensor 138 (and in some embodiments the needle 156) into theskin of the host; and a needle retraction mechanism 158 m configured tounlock the needle hub 162 m from the first portion 150 m (e.g., to allowproximal movement of the needle hub 162 m with respect to the firstportion 150 m) at least once the needle hub 162 m has reached asufficiently distal position and thereby enable a second spring 234 m toretract the needle 156).

FIG. 71 illustrates a cross-sectional perspective view of the applicatorsystem 104 m in a resting state (e.g., as provided to the consumer,before activation by the user and deployment of the applicator system).As illustrated in the figure, the first spring 402 m can be neither intension nor compression, such that the first spring is substantiallyunenergized. In some embodiments, the first spring 402 m can be slightlyin tension or slightly in compression (e.g., neither tensioned norcompressed by more than 15 percent) in a resting state, such that thefirst spring is substantially or mostly unenergized in the restingstate. In some embodiments, the first spring can be effectivelyunenergized, e.g. can be minimally energized but not to an extent thatwould create any type of chain reaction in the system, in a restingstate.

In the embodiment illustrated in FIGS. 71-75 , the first spring 402 m isintegrally formed as part of the third portion 392 m. In someembodiments, the first spring 402 m can be integrally formed as part ofother components of the system 104 m, such as, but not limited to, thefirst portion 150 m, second portion 152 m, etc. An integrally formedspring such as the one illustrated in FIGS. 71-75 offers advantagesincluding the reduction in the number of parts in a system as well asthe reduction in the amount of assembly processes. The first spring 402m can be molded plastic. As illustrated in FIG. 71 , in the restingstate, the second spring 234 m is also substantially unenergized (e.g.,neither tensioned nor compressed by more than 15 percent). The secondspring 234 m is integrally formed as part of the needle hub 162 m. Insome embodiments, the second spring 234 m can be integrally formed aspart of other components of the system 104 m, such as, but not limitedto, the first portion 150 m, second portion 152 m, base 128, etc. Thesecond spring 234 m can be molded plastic. Such a configuration cansimplify manufacture and assembly of the system 104 m, while avoidingdetrimental relaxation and/or creep of the first spring 402 m, thesecond spring 234 m, or other components of the system 104 m duringstorage and/or before deployment. It is also contemplated that in otherembodiments, the first spring 402 m and/or the second spring 234 m cancomprise metal.

In some embodiments, first spring 402 m and/or second spring 234 m cancomprise a molded plastic, such as, but not limited to: polycarbonate(PC), acrylonitrile butadiene styrene (ABS), PC/ABS blend, Nylon,polyethylene (PE), polypropylene (PP), and Acetal. In some embodiments,first spring 402 m and/or second spring 234 m have a spring constantless than 10 lb/inch.

Applicator system 104 may be energized by moving one component relativeto another. For example, moving the third portion 392 m distallyrelative to the second portion 152 m, when the second portion 152 m isplaced against the skin of a host or another surface can store energy inthe first spring 402 m as it compresses against first portion 150 m. Thethird portion 392 m may be moved distally until the locking features 408m and 410 m (see FIG. 73 ) engage together. In some embodiments, thethird portion 392 m may be moved further distally until unlockingfeatures 404 m engages locking feature 396 m. Unlocking feature 404 mmay engage and release locking feature 396 m and allow first portion 150m to move distally. In some embodiments, locking features 408 m and 410m couple together before locking feature 396 m is disengaged fromlocking feature 398 m. In other embodiments, unlocking feature 404 mengages locking feature 396 m and causes locking feature 396 m todisengage from locking feature 398 m, locking features 408 m and 410 mmay couple together. In some embodiments, locking feature 408 m is aprotrusion featuring a hook portion, locking feature 410 m is a holefeaturing an angled surface, unlocking feature 404 m is a distalprotrusion featuring an angled surface, locking feature 396 m is a hookfeaturing a ramp 406 m, and locking feature 398 m is an aperture. Thesensor module 134 remains in a proximal starting position while thefirst spring 402 m is being energized.

FIG. 72 illustrates a cross-sectional perspective view of the applicatorsystem 104 m, with the first spring 402 m compressed and with theunlocking features 404 m and 406 m engaged so as to unlock the firstportion 150 m from the second portion 152 m. Until the first portion 150m is unlocked from the second portion 152 m, the sensor module 134remains at its proximal starting position, and the second spring 234 mremains substantially unenergized. FIG. 73 illustrates a rotatedcross-sectional perspective view of the applicator system 104 m, andshows the locking features 408 m and 410 m engaged to prevent proximalmovement of the third portion 392 m with respect to the second portion152 m. In some embodiments, as illustrated in FIG. 73 , the system caninclude a secondary locking feature 409 m which is configured tocooperate with the opening 410 m to prevent the third portion 392 fromfalling off or otherwise separating from the remainder of the system 104m prior to deployment.

FIG. 74 illustrates a cross-sectional perspective view of the applicatorsystem 104 m, with the system 104 m having been activated by thedisengagement of the first portion 150 m with respect to the secondportion 152 m. As can be seen in FIG. 74 , once the first portion 150 mand the second portion 152 m are disengaged or released, the potentialenergy stored in the first spring 402 m drives the first portion 150 min a distal direction along with the needle hub 162 m and the sensormodule 134. This movement compresses the second spring 234 m and deploysthe needle 156 and the sensor module 134 distally to a distal insertionposition in which the sensor module 134 is coupled to the base 128 andthe needle 156 extends distally of the base 128. Once the needle 156 andthe sensor module 134 reach the distal insertion position, the lockingfeatures 412 m, 414 m (see FIG. 73 ) engage to prevent proximal movementof the first portion 150 m with respect to the second portion 152 m, andthe unlocking features of the needle retraction mechanism 158 m (e.g.,the proximal protrusions 170 m, the release feature 160 m, and the latch236 m comprising ends 164 m of the release feature 160 m and overhangs166 m of the first portion 150 m) cooperate to release the latch 236 m.Optionally, the user may hear a click after the second spring 243 m isactivated, which may indicate to the user that the cap is locked inplace.

Once the latch 236 m is released, the potential energy stored in thecompressed second spring 234 m drives the needle hub 162 m back in aproximal direction, while the first portion 150 m remains in a distaldeployed position along with the sensor module 134. The potential energystored can be between 0.25 pounds to 4 pounds. In preferred embodiments,the potential energy stored is between about 1 to 2 pounds. FIG. 75illustrates a cross-sectional perspective view of the applicator system104 m with the sensor module 134 in a distal deployed position, coupledto the base 128, and with the needle hub 162 m retracted to a proximalretracted position.

Systems configured in accordance with embodiments may provide aninherently safe and shelf stable system for insertion of a sensor. Anunloaded (i.e. substantially uncompressed and substantially unactivated)spring may not fire prematurely. Indeed, such a system is largelyincapable of unintentional firing without direct interaction from a usersince the first spring and/or second spring are substantiallyun-energized on the shelf. Moreover, it is contemplated that a systemhaving a substantially uncompressed spring prior to activation possessesshelf stability since elements of the system are not exposed to a forceor phase change over time (such as creep, environment, defects from timedependent load conditions, etc.) as compared to pre-energized insertiondevices. Substantially uncompressed first and second springs can providea system where the substantially unenergized first spring 404 m isconfigured to load energy sufficient to drive a sensor from a proximalposition to a distal position and also to transfer energy to the secondspring 234 m to drive a needle to a fully retracted position.

Other embodiments can also be configured to achieve these benefits. Forexample, FIGS. 76-79 illustrate another embodiment of a system 104 n forapplying an on-skin sensor assembly to skin of a host. The system 104 nincludes many features that are similar to those of the embodimentillustrated in FIGS. 71-75 (e.g., a telescoping assembly 132 n includinga first portion 150 n, a second portion 152 n, and a third portion 392n; a needle hub 162 n; a first spring 402 n; and a second spring 234 n).In the embodiment illustrated in FIGS. 76-79 , the first spring 402 n isformed separately from and operatively coupled to the third portion 392n. The second spring 234 n is formed separately from and operativelycoupled to the needle hub 162 n. The first spring and/or the secondspring can each comprise a helical spring having a circular crosssection. In some embodiments, the first spring and/or the second springcan each comprise a helical spring having a square or non-circular crosssection. The first spring and/or the second spring can comprise metal,such as, but not limited to, stainless steel, steel, or other types ofmetals. Alternatively, in some embodiments, one or both of the firstspring and the second spring can be integrally formed with a portion ofthe applicator assembly. For example and without limitation, in someembodiments the first spring can be integrally formed with the firstportion. In some embodiments, the second spring can be integrally formedwith the needle hub. In several embodiments, the first spring and/or thesecond spring can be molded plastic, such as, but not limited to, PC orABS.

FIG. 76 illustrates a cross-sectional side view of the system 104 n in aresting state, in which both the first spring 402 n and the secondspring 234 n are unstressed and unenergized. In the resting state, thefirst portion 150 n can be fixed with respect to the second portion 152n, at least in an axial direction, whereas the third portion 392 n ismovable in at least a distal direction with respect to the first portion150 n. The first portion 150 n and the second portion 152 n can be fixedwith respect to one another in any suitable fashion, for example bycooperating releasable locking features (e.g., the locking features asdescribed in FIGS. 71-75 , or similar features) coupled to or formingpart of the first portion 150 n and the second portion 152 n. The system104 n includes an on-skin component 134 n which is releasably coupled tothe needle hub 162 n. The on-skin component can comprise a sensormodule, such as the sensor module 134 described in connection with FIG.3 , or a combined sensor module and base assembly, or an integratedsensor module/base/transmitter assembly, or any other component which isdesirably applied to the skin of a host, whether directly or indirectly,for example via an adhesive patch.

In the resting state illustrated in FIG. 76 , the on-skin component 134n is disposed at a proximal starting position, between the proximal anddistal ends of the system 104 n. The distal end of the needle 156 mayalso be disposed between the proximal and distal ends of the system 104n. In the resting state, the distal end of the first spring 402 n abutsa proximally-facing surface of the first portion 150 n. The applicationof force against the proximally-facing surface of the third portion 392n causes the third portion 392 n to move distally with respect to thefirst portion 150 n, compressing and thus energizing the first spring402 n. In some embodiments, this process may be similar to the springenergization process described in connection with FIG. 71 .

FIG. 77 illustrates a cross-sectional side view of the applicator systemof FIG. 76 , with the first spring 402 n energized. When the thirdportion 392 n has been moved sufficiently distally to energize the firstspring 402 n, the third portion 392 n becomes fixed, at least in anaxial direction, with respect to the second portion 152 n. At or aboutthe same time (e.g. simultaneously or subsequently), the first portion150 n becomes movable in at least a distal direction with respect to thesecond portion 152 n. The third portion 392 n and the second portion 150n can be fixed with respect to one another in any suitable fashion, forexample by cooperating locking features (e.g., the locking featuresdescribed in FIGS. 71-75 , or similar features) coupled to or formingpart of the third portion 392 n and the second portion 152 n, which areconfigured to engage with one another once the third portion 392 n hasreached a sufficiently distal position. The first portion 150 n and thesecond portion 152 n can be rendered movable with respect to one anotherby structure(s) (not shown in FIGS. 76-79 ) configured to release thelocking features which coupled them together in the restingconfiguration illustrated in FIG. 76 . The first portion 150 n includesoverhangs (sometimes referred to as detents, undercuts, and/or needlehub engagement features) 166 n which cooperate with release feature 160n of the needle hub 162 n to fix the needle hub 162 n with respect tothe first portion 150 n, both while the system is in a resting state andduring energization of the spring 392 n.

FIG. 78 illustrates a cross-sectional side view of the system 104 n,with the first portion 150 n and the second portion 152 n unlocked,activating the first spring 402 n and allowing the energy stored thereinto drive the first portion 150 n in a distal direction. The movement ofthe first portion 150 n also urges the needle hub 162 n (as well as theon-skin component 134 n which is coupled to the needle hub 162 n) in adistal direction, compressing the second spring 234 n against aproximally-facing surface of the second portion 152 n, coupling theon-skin component 134 n to the base 128 n, and driving the needle 156into the distal insertion position illustrated in FIG. 78 . When theneedle hub 162 n has reached a sufficiently distal position to achievethese functions, the ends of the release feature 160 n contact ramps 170n of the second portion 152 n which cause the release feature 160 n tocompress inward (towards the central axis of the system 104 n),disengaging the ends of the release feature 160 n from the overhangs 166n. In some embodiments, this process may be similar to the springcompression process described in connection with FIG. 74 . In someembodiments, ramps 170 n are proximally facing ramps. In otherembodiments, ramps 170 n are distally facing ramps (not shown). In someembodiments, the release feature or features can be configured to becompressed inward (or otherwise released) by relative rotationalmovement of certain components of the system, such as, for example, bytwisting or other rotational movement of the first portion with respectto the second portion. In some embodiments, the release feature orfeatures can extend in a direction normal to the axis of the system,and/or can extend circumferentially about the axis of the system,instead of (or in addition to) extending generally parallel to the axisof the system as illustrated in FIG. 78 .

FIG. 79 illustrates a cross-sectional side view of the system 104 n,with the needle hub 162 n released from engagement with the overhangs166, activating the second spring 234 n and allowing the energy storedtherein to drive the needle hub 162 n in a proximal direction. As theneedle hub 162 n retracts to a proximal position, the on-skin component134 n decouples from the needle hub 162 n to remain in a deployedposition, coupled to the base 128 n.

FIGS. 80-85 illustrate another embodiment of a system 104 p for applyingan on-skin sensor assembly to skin of a host. A sensor insertion systemsuch as the one illustrated in FIGS. 80-85 may provide enhancedpredictability in spring displacement of the second energized spring 234p because the second spring 234 p is already compressed. Such aconfiguration can aid in properly ensuring the needle is retracted at asufficient distance from the skin. In some embodiments, a systemincorporating a pre-energized retraction spring can provide effectiveand reliable insertion and retraction while requiring a lesser amount ofuser-supplied force than, for example, a system in which both theinsertion and retraction springs are substantially unenergized prior todeployment, making such a configuration more convenient for at leastsome users. Further, in some embodiments, a system incorporating one ormore metal springs can provide effective and reliable insertion andretraction while requiring a lesser amount of force than a system inwhich both the insertion and retraction springs comprise plastic. Thesystem 104 p includes many features that are similar to those of theembodiment illustrated in FIGS. 76-79 (e.g., a telescoping assembly 132p including a first portion 150 p, a second portion 152 p, and a thirdportion 392 p; a needle hub 162 p; a first spring 402 p; a second spring234 p; an on-skin component 134 n, and a base 128 p). In the embodimentillustrated in FIGS. 80-85 , the first spring 402 p is formed separatelyfrom and operatively coupled to the third portion 392 p. The secondspring 234 p is formed separately from and operatively coupled to theneedle hub 162 p. The first spring and/or the second spring can comprisemetal. Alternatively, in some embodiments, one or both of the firstspring and the second spring can be integrally formed with a portion ofthe applicator assembly. For example and without limitation, in someembodiments the first spring can be integrally formed with the firstportion. In some embodiments, the second spring can be integrally formedwith the needle hub. In several embodiments, the first spring and/or thesecond spring can be molded plastic.

FIG. 80 illustrates a cross-sectional side view of the system 104 p in aresting state, in which the first spring 402 p is substantiallyunstressed and unenergized, but in which the second spring 234 n ispre-energized (e.g., compressed). In the resting state illustrated inFIG. 80 , the first portion 150 p is locked to the second portion 152 pso as to prevent proximal or distal movement of the first portion 150 pwith respect to the second portion 152 p. The first portion 150 p andthe second portion 152 n can be locked together in any suitable fashion,for example by cooperating releasable locking features 396 p and 398 p(see FIGS. 84 and 85 ) coupled to or forming part of the first portion150 p and the second portion 152 p. The needle hub 162 n is alsoreleasably fixed to the first portion 150 p. The needle hub 162 n can befixed to the first portion 150 p in any suitable fashion, for example byfeatures of the first portion 150 p configured to engage or compressrelease feature (sometimes referred to as needle hub resistancefeatures) 160 p of the needle hub 162 p.

In the resting state illustrated in FIG. 80 , the on-skin component 134p is disposed at a proximal starting position, such that the distal endof the needle 156 is disposed between the proximal and distal ends ofthe system 104 p. In the resting state, the distal end of the firstspring 402 p abuts a proximally-facing surface of the first portion 150p. The application of force against the proximally-facing surface of thethird portion 392 p causes the third portion 392 p to move distally withrespect to the first portion 150 p, compressing and thus energizing thefirst spring 402 p. In some embodiments, this process may be similar tothe spring energization process described in connection with FIG. 76 .

FIG. 81 illustrates a cross-sectional side view of the system 104 p ofFIG. 80 , after the third portion 392 n has been moved to a sufficientlydistally position to energize the first spring 402 p and optionally lockthe third portion 392 p to the second portion 152 p. The third portion392 n and the second portion 150 n can lock together in any suitablefashion, for example by cooperating locking features (e.g., the lockingfeatures described in FIGS. 76-79 , or similar features) coupled to orforming part of the third portion 392 p and the second portion 152 p. Ator about the same time as the third portion 392 p locks to the secondportion 152 p (e.g. simultaneously or subsequently), the unlockingfeatures 404 p and 406 p (see FIGS. 84 and 85 ) cooperate to release thelock between the first portion 150 p and the second portion 152 p.

FIG. 82 illustrates a cross-sectional side view of the system 104 p,with the first spring 402 p activated to drive the first portion 150 pin a distal direction. The movement of the first portion 150 p alsourges the needle hub 162 p (as well as the on-skin component 134 p whichis coupled to the needle hub 162 p) in a distal direction, coupling theon-skin component 134 p to the base 128 p, and also driving the needle156 in a distal direction, past a distal end of the system 104 p. At orabout the time the needle hub 162 p reaches the distal insertionposition illustrated in FIG. 82 (e.g., immediately before,simultaneously, or subsequently), the ends of the release feature 160 pcontact ramps 170 p of the second portion 152 p, causing the releasefeature 160 p to compress inward (towards the central axis of the system104 p), unlocking the needle hub 162 p from the first portion 150 p andreleasing or activating the second spring 234 p. In some embodiments,ramps 170 p are proximally facing ramps. In other embodiments, ramps 170p are distally facing ramps (not shown). Activation of the second spring234 p urges the needle hub 162 p in a proximal direction.

FIG. 83 illustrates a cross-sectional side view of the system 104 p,with the needle hub 162 p unlocked from the first portion 150 p andretracted to a proximal position. As the needle hub 162 p retracts to aproximal position, the on-skin component 134 p decouples from the needlehub 162 p to remain in a deployed position, coupled to the base 128 p.

FIG. 84 illustrates a perspective view of the system 104 p in a restingstate, with the first portion 150 p and the third portion 392 p shown incross section to better illustrate certain portions of the system 104 p,such as the locking features 396 p, 398 p and the unlocking features 404p, 406 p. FIG. 85 illustrates another perspective view of the system 104p, also with the first portion 150 p and the third portion 392 p shownin cross section, with the first spring 402 p energized but not yetactivated.

FIGS. 86-88 illustrate another embodiment of a system 104 q for applyingan on-skin sensor assembly to skin of a host, wherein the insertionspring is pre-compressed and the retraction spring is substantiallyuncompressed. Such a system may allow a user to activate the insertionand retraction of a needle with fewer steps. It is contemplated thatadvantages may include a relatively smaller applicator size and morepredictable spring displacement of the first spring because the firstspring is already compressed, thereby aiding in ensuring proper needleinsertion into the skin of a user. In some embodiments, a systemincorporating a pre-energized insertion spring can provide effective andreliable insertion and retraction while requiring a lesser amount ofuser-supplied force than, for example, a system in which both theinsertion and retraction springs are substantially unenergized prior todeployment, making such a configuration more convenient for at leastsome users. The system 104 q includes many items that are similar tothose of the embodiment illustrated in FIGS. 76-79 (e.g., a telescopingassembly 132 q including a first portion 150 q, a second portion 152 q,and a third portion 392 q; a needle hub 162 q; a first spring 402 q; asecond spring 234 q; an on-skin component 134 q, and a base 128 q). Inthe system 104 q, the first spring 402 q is formed separately from andoperatively coupled to the third portion 392 q. The second spring 234 qis formed separately from and operatively coupled to the needle hub 162q. The first spring and/or the second spring can comprise metal.Alternatively, in some embodiments, one or both of the first spring andthe second spring can be integrally formed with a portion of theapplicator assembly.

FIG. 86 illustrates a cross-sectional side view of the system 104 q in aresting state, in which the first spring 402 q is already energized butin which the second spring 234 q is substantially unenergized (e.g.mostly uncompressed or unstressed; can be partially energized). In theresting state illustrated in FIG. 86 , the first portion 150 q is lockedto the second portion 152 q so as to prevent proximal or distal movementof the first portion 150 q with respect to the second portion 152 q. Thefirst portion 150 q and the second portion 152 q can be locked togetherin any suitable fashion, for example by cooperating releasable lockingfeatures (e.g., the locking features described in FIGS. 76-79 or othersuitable locking features) coupled to or forming part of the firstportion 150 q and the second portion 152 q. The needle hub 162 q is alsoreleasably locked to the first portion 150 q. The needle hub 162 q canbe locked to the first portion 150 q in any suitable fashion, forexample by features of the first portion 150 q configured to engage orcompress release feature 160 q of the needle hub 162 q. The thirdportion 392 q and the second portion 152 q are also locked together, soas to prevent relative movement of the third portion 392 p and thesecond portion 152 q in the axial direction. The third portion 392 q andthe second portion 152 q can be locked together in any suitable fashion,for example by cooperating locking features (not shown in FIGS. 86-89 ),which may be coupled to or form part of the third portion 392 q and thesecond portion 152 q. In the resting state illustrated in FIG. 80 , theon-skin component 134 q is disposed at a proximal starting position,such that the distal end of the needle 156 is disposed between theproximal and distal ends of the system 104 q.

To trigger deployment of the system 104 q, the locking features couplingthe first portion 150 q to the second portion 152 q can be unlocked,decoupling these two portions and thereby releasing or activating thefirst spring 402 q. The locking features can be unlocked by auser-activated trigger mechanism, such as, for example, a buttondisposed on or in a top or side surface of the system 104 q, or atwist-release feature configured to disengage the locking features whenthe third portion 392 q is rotated about the axis of the system,relative to the first portion 150 q and/or the second portion 152 q.Some examples of triggering mechanisms are described in connection withFIGS. 92-104 .

FIG. 87 illustrates a cross-sectional side view of the system 104 q,after the first portion 150 q and the second portion 152 q have beenunlocked. As can be seen in FIG. 87 , the first spring 402 q drives thefirst portion 150 q in a distal direction as the first spring 402 qexpands. The movement of the first portion 150 q also urges the needlehub 162 q (as well as the on-skin component 134 q which is coupled tothe needle hub 162 q) in a distal direction, coupling the on-skincomponent 134 q to the base 128 q, compressing the second spring 234 q,and driving the needle 156 in a distal direction past a distal end ofthe system 104 q. At or about the time the needle hub 162 q reaches thedistal insertion position illustrated in FIG. 87 (e.g., immediatelybefore, simultaneously, or subsequently), the ends of the releasefeature 160 q contact interference features 170 q of the second portion152 q, causing the release feature 160 q to compress inward (towards thecentral axis of the system 104 q), unlocking the needle hub 162 q fromthe first portion 150 q and activating the now-energized second spring234 q. In some embodiments, interference features 170 q are proximallyfacing interference features. In other embodiments, interferencefeatures 170 q are distally facing interference features (not shown).

Activation of the second spring 234 q by the user or mechanisms urgesthe needle hub 162 q in a proximal direction, while the on-skincomponent 134 q, having been coupled to the base 128 q, remains in adeployed distal position. FIG. 88 illustrates a cross-sectional sideview of the system 104 q, with the on-skin component 134 q in a deployedposition and the needle hub 162 q retracted to a proximal position.

FIGS. 89-91 illustrate another embodiment of a system 104 r for applyingan on-skin sensor assembly to skin of a host. It is contemplated thatthe system 104 r as illustrated with reference to FIGS. 89-91 providesfor predictable spring displacement of the first spring 402 r because itis compressed, thereby aiding in proper needle insertion into the skinof the user. Moreover, it is contemplated that the compressed secondspring 234 r provides predictable spring displacement and aids inproperly ensuring that the needle is properly retracted from the skin ofthe user. In some embodiments, a system incorporating pre-energizedinsertion and retraction springs can provide effective and reliableinsertion and retraction while requiring a lesser amount ofuser-supplied force than, for example, a system in which one or both ofthe insertion and retraction springs are substantially unenergized priorto deployment, making such a configuration more convenient for at leastsome users. The system 104 r includes many items that are similar tothose of the embodiment illustrated in FIGS. 76-79 (e.g., a telescopingassembly 132 r including a first portion 150 r, a second portion 152 r,and a third portion 392 r; a needle hub 162 r; a first spring 402 r; asecond spring 234 r; an on-skin component 134 r, and a base 128 r). Asillustrated in FIGS. 89-91 , both the first spring 402 r and the secondspring 234 r are pre-compressed. In the system 104 r, the first spring402 r is formed separately from and operatively coupled to the thirdportion 392 r. The second spring 234 r is formed separately from andoperatively coupled to the needle hub 162 r. The first spring and/or thesecond spring can comprise metal. Alternatively, in some embodiments,one or both of the first spring and the second spring can be integrallyformed with a portion of the applicator assembly.

FIG. 89 illustrates a cross-sectional side view of the system 104 r in aresting state, in which both the first spring 402 r and the secondspring 234 r are pre-energized (e.g., compressed sufficiently to drivethe needle insertion and retraction processes). In the resting stateillustrated in FIG. 89 , the first portion 150 r is locked to the secondportion 152 r so as to prevent proximal or distal movement of the firstportion 150 r with respect to the second portion 152 r. The firstportion 150 r and the second portion 152 r can be locked together in anysuitable fashion, for example by cooperating releasable locking features(e.g., the locking features described in connection with FIGS. 80-83 ,or other suitable locking features) coupled to or forming part of thefirst portion 150 r and the second portion 152 r. The needle hub 162 ris also releasably locked to the first portion 150 r. The needle hub 162r can be locked to the first portion 150 r in any suitable fashion, forexample by features of the first portion 150 r configured to engage orcompress release feature 160 r of the needle hub 162 r. The thirdportion 392 r and the second portion 152 r are also locked together, soas to prevent relative movement of the third portion 392 p and thesecond portion 152 r in at least the axial direction. The third portion392 r and the second portion 152 r can be locked together in anysuitable fashion, for example by cooperating locking features (not shownin FIGS. 89-91 ), which may be coupled to or form part of the thirdportion 392 r and the second portion 152 r. In the resting stateillustrated in FIG. 89 , the on-skin component 134 r is disposed at aproximal starting position, such that the distal end of the needle 156is disposed between the proximal and distal ends of the system 104 r.

To trigger deployment of the system 104 r, the locking features couplingthe first portion 150 r to the second portion 152 r can be unlocked,decoupling these two portions and thereby releasing or activating thefirst spring 402 r. FIG. 90 illustrates a cross-sectional side view ofthe system 104 r, after the first portion 150 r and the second portion152 r have been unlocked. As can be seen in FIG. 90 , the first spring402 r drives the first portion 150 r in a distal direction as the firstspring 402 r expands or decompresses. The movement of the first portion150 r also urges the needle hub 162 r (as well as the on-skin component134 r which is coupled to the needle hub 162 r) in a distal directionuntil the on-skin component 134 r is coupled to the base 128 r, anduntil the needle 156 reaches a distal insertion position beyond a distalend of the system 104 r. At or about the time the needle hub 162 rreaches the distal insertion position illustrated in FIG. 87 (e.g.,immediately before, simultaneously, or subsequently), the ends of therelease feature 160 r contact corresponding interference features 170 rof the second portion 152 r, causing the release feature 160 r tocompress inward (towards the central axis of the system 104 r),unlocking the needle hub 162 r from the first portion 150 r andreleasing or activating the second spring 234 r.

Activation of the second spring 234 r drives the needle hub 162 r in aproximal direction, while the on-skin component 134 r, having beencoupled to the base 128 r, remains in a deployed distal position. FIG.91 illustrates a cross-sectional side view of the system 104 r, with theon-skin component 134 r in a deployed position and the needle hub 162 rretracted to a proximal position. From this configuration, the system104 r can be removed and separated from the deployed on-skin component134 r and the base 128 r.

FIGS. 92-100 illustrate yet another embodiment of a system 104 s forapplying an on-skin sensor assembly to skin of a host comprising asafety feature to prevent accidental firing of the sensor insertiondevice. The system 104 s includes many items that are similar to thoseof the embodiment illustrated in FIGS. 76-79 (e.g., a telescopingassembly 132 s including a first portion 150 s, a second portion 152 s,and a third portion 392 s; a needle hub 162 s; a first spring 402 s; asecond spring 234 s; an on-skin component 134 s, and a base 128 s). Inthe system 104 s, the first spring 402 s may be formed separately fromand operatively coupled to the third portion 392 s. The second spring234 s may be formed separately from and operatively coupled to theneedle hub 162 s. The first spring and/or the second spring can comprisemetal. Alternatively, in some embodiments, either or both of the firstspring and the second spring can be integrally formed with a portion ofthe applicator assembly.

FIG. 92 illustrates a side view of the system 104 s in a resting state,in which the first spring 402 s is unstressed and unenergized, but inwhich the second spring 234 s is already energized (e.g., compressed).The system 104 s includes a cocking mechanism 702 by which the firstspring 402 s can be energized (e.g. compressed) without automaticallytriggering deployment of the first portion 150 s or activation of thefirst spring 402 s. The system 104 s also includes a trigger button 720configured to activate the first spring 402 s after the system iscocked. FIG. 93 illustrates a side view of the applicator system 104 s,after being cocked but before being triggered.

FIG. 94 illustrates a cross-sectional perspective view of the system 104s in a resting state, showing the first spring 402 s substantiallyuncompressed. The cocking mechanism 702 includes a pair ofproximally-extending lever arms 704, each with a radially-extendingangled tab 706. In some embodiments, the lever arms 704 can beintegrally formed with the second portion 152 s, as shown in FIG. 94 ,while in other embodiments, the lever arms 704 can be separate from andoperatively coupled to the second portion 152 s. In the resting stateillustrated in FIG. 94 , the angled tabs 706 extend through distalapertures 708 in the third portion 392 s so as to prevent proximalmovement of the third portion 392 s with respect to the second portion152 s. The angled tabs 706 are also configured to inhibit distalmovement of the third portion 392 s with respect to the second portion152 s, unless and until a sufficient amount of force is applied to thethird portion 392 s to deflect the angled tabs 706 and the lever arms704 inward, as illustrated in FIG. 95 .

As sufficient force is applied to the third portion 392 s in a distaldirection (e.g. by the hand or thumb of a user), the angled tabs 706deflect inward and release from engagement with the distal apertures708, allowing the third portion 392 s to move distally with respect tothe second portion 152 s. This may allow the user to compress andenergize the first spring 402 s. When the third portion 392 s hasreached a sufficiently distal position to compress the first spring 402s enough to drive the sensor into the skin of a host, the angled tabs706 engage with proximal apertures 710 of the third portion 392 s tolock the position of the third portion 392 s with respect to the secondportion 152 s, as illustrated in FIG. 96 . The angled tabs 706 may beconfigured to generate a “click” sound when engaged to proximalapertures 710 so as to prevent proximal movement of the third portion392 s with respect to the second portion 152 s, so that a user can feeland/or hear when these parts are engaged. In the configurationillustrated in FIG. 96 , the system 104 s is energized in which thethird portion 392 is in a cocked position. The system 104 s is ready todeploy the sensor, but does not deploy until further action is taken bythe user.

FIG. 97 illustrates a cross-sectional side view of the system 104 s, ina cocked but untriggered state. In this state, the first portion 150 sis locked to the second portion 152 s so as to prevent proximal ordistal movement of the first portion 150 s with respect to the secondportion 152 s. The first portion 150 s and the second portion 152 s canbe locked together in any suitable fashion, for example by cooperatingreleasable locking features 396 s and 398 s operatively coupled to orforming part of the first portion 150 s and the second portion 152 s.The trigger button 720 includes a distally-extending protrusion 722which, once depressed to a sufficiently distal position by a user, isconfigured to cooperate with an unlocking feature 406 s of the lockingfeature 396 s to decouple the first portion 150 s from the secondportion 152 s. The trigger button 720 can be operatively coupled to thethird portion 392 s, as illustrated in FIGS. 92-100 , or can beintegrally formed with the third portion, for example as a lever armformed within a proximal or side surface of the third portion. In someembodiments, the trigger button can be disposed at the top of the system(such that the application of force in the distal direction triggers thesystem to activate), or at a side of the system (such that theapplication of force in a radially inward direction, normal to thedirection of needle deployment, triggers system to activate).

FIG. 98 illustrates a cross-sectional side view of the energized system104 s as the trigger button 720 has been depressed sufficiently to causethe protrusion 722 to flex the locking feature 396 s radially inward,disengaging it from the opening 398 s and unlocking the first portion150 s from the second portion 152 s. Depressing the trigger button 720thus activates the first spring 402, pushing the first portion 150 s andthe needle hub 162 s, along with the on-skin component 134 s which iscoupled thereto, in a distal direction until the on-skin component iscoupled to the base 128 s, as illustrated in FIG. 99 . At or about thetime the needle hub 162 s reaches the distal insertion positionillustrated in FIG. 99 (e.g., immediately before, simultaneously, orsubsequently), corresponding release features of the needle hub 162 sand the first portion 150 s can engage (via, for example, the releasefeatures described in any of FIGS. 76-91 , or any other suitable releasefeatures), releasing the needle hub 162 s from the first portion 150 sand releasing or activating the second spring 234 s. Activation of thesecond spring 234 s urges the needle hub 162 s in a proximal direction.

FIG. 100 illustrates a cross-sectional side view of the applicatorsystem of FIG. 92 , with the on-skin component 134 s in a deployedposition and the needle hub 162 s retracted to a proximal position. Asthe needle hub 162 s retracts to a proximal position, the on-skincomponent 134 s decouples from the needle hub 162 s to remain in adeployed position, coupled to the base 128 s. From this configuration,the remainder of the system 104 s can be removed and separated from thedeployed on-skin component 134 s and the base 128 s.

Any of the features described in the context of any of FIGS. 61-99 canbe applicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 61-64 can becombined with the embodiments described in the context of FIGS. 1-60 and65-70 . As another example, any of the embodiments described in thecontext of FIGS. 92-109 can be combined with any of the embodimentsdescribed in the context of FIGS. 1-60 and 65-91 and 110-143 . Moreover,any of the features of an embodiment is independently combinable, partlyor wholly with other embodiments described herein in any way, e.g., one,two, or three or more embodiments may be combinable in whole or in part.Further, any of the features of an embodiment may be made optional toother aspects or embodiments. Any aspect or embodiment of a method canbe performed by a system or apparatus of another aspect or embodiment,and any aspect or embodiment of a system can be configured to perform amethod of another aspect or embodiment.

Trigger Mechanisms and Safety Locks

In some embodiments, the application of enough force to sufficientlyenergize the first spring to drive insertion of the sensor can alsoserve to activate the first spring. In other embodiments, the energizingof the first spring can be decoupled from the activation of the firstspring, requiring separate actions on the part of the user to energize(e.g. compress) the first spring and to trigger deployment of thesystem.

For example, the embodiment illustrated in FIGS. 92-100 includes atrigger mechanism in the context of a user-energized actuator. In suchan embodiment, the user first cocks the system 104 s to energize thefirst spring 402 s, and then, in a separate action, triggers theactivation of the first spring 402 s using the trigger button 720. Thelocking feature is easy to release by the user and when combined with atrigger mechanism, allows for single handed use.

In some embodiments, the actuator or insertion spring is alreadyenergized when the system is in a resting state. In these embodiments, atrigger mechanism, such as the trigger mechanism described in thecontext of FIGS. 92-100 , can be used to activate the already-energizedinsertion spring without any action by the user to energize the spring.

FIG. 101 illustrates a side view of one such applicator system 104 t,with a side trigger button 730. The system 104 t can be configuredsubstantially similar to the system 104 q or the system 104 rillustrated within the context of FIGS. 86-88 and 89-91 , respectively,with like reference numerals indicating like parts. As can be seen inFIG. 101 , the trigger button 730 is operatively coupled to the thirdmember 392 t.

FIG. 102 illustrates another side view of the system 104 t, with thefirst portion 150 t and the third portion 392 t shown in cross-sectionto illustrate the trigger mechanism. As can be seen in FIG. 102 , thetrigger button 730 includes a protrusion 732 that extends radiallyinward, toward a central axis of the system 104 t. The protrusion 732 isradially aligned with the locking feature 396 t of the first portion 150t. When a user exerts a sideways (e.g., radially inward) force on thetrigger button 730, the protrusion 732 urges the locking feature 396 tradially inward, releasing it from engagement with the ledge feature 398t (which may be configured similarly to, for example, the ledge lockingfeature 398 p illustrated in FIGS. 84 and 85 ) in the second portion 152t and activating the first spring 402 t. In other embodiments, thelocking features 396, 398 can comprise cooperating structure of akey/keyway mechanism which is configured to release when the features396, 398 are brought into a certain orientation with respect to oneanother (e.g., using a radially applied force, an axially applied force,a twisting movement or rotational force, or other type of activation).

FIG. 103 illustrates a side view of another applicator system 104 u,with an integrated side trigger button 730. The system 104 u can beconfigured substantially similar to the system 104 q or the system 104 rillustrated within the context of FIGS. 86-88 and 89-91 , respectively,with like reference numerals indicating like parts. As can be seen inFIG. 103 , the trigger button 740 is a distally-extending lever armintegrally formed in the third member 392 u. FIG. 104 illustratesanother side view of the system 104 u, with the first portion 150 u andthe third portion 392 u shown in cross-section to better illustrate thetrigger mechanism. As can be seen in FIG. 104 , the trigger button 740is radially aligned with a radially-extending tab 742 of the firstportion 150 u. The tab 742 is connected to the locking feature 396 u viaan elongated member 394 u, which acts as a lever arm. In someembodiments, tab 742 locking feature 396 u, and elongated member 394 uare integrally formed together. When a user exerts a sideways (e.g.,radially inward) force on the trigger button 740, the button 740 pushesthe tab 742 radially inward, releasing the locking feature 396 u fromengagement with the locking feature 398 u in the second portion 152 uand activating the first spring 402 u.

Trigger mechanisms such as those described in the context of any ofFIGS. 92-104 can be used in embodiments comprising pre-energizedactuators or insertion springs, as well as in embodiments comprisinguser-energized actuators or insertion springs.

In several embodiments, a sensor inserter system can include a safetymechanism configured to prevent premature energizing and/or actuation ofthe insertion spring. FIGS. 105-109 illustrate one such system 104 v,which incorporates a safety lock mechanism 750. FIG. 105 illustrates aperspective view of the system 104 v. The system 104 v can be configuredsubstantially similar to any of the systems 104 m, 104 n, 104 pillustrated within the context of FIGS. 71-87 , with like referencenumerals indicating like parts. The safety lock mechanism 750 includes arelease button 760, which can be integrally formed with the thirdportion 392 v as shown in FIG. 105 (similar to the trigger button 740described in connection with FIGS. 103-104 ), or which can beoperatively coupled to the third portion 392 v. In the system 104 v, therelease button 760 comprises a lever arm which is integrally formed in aside of the third portion 392 v, although other configurations (e.g. atop button) are also contemplated. The release button can be configuredto protrude radially from a side or a top of the third portion, or canbe configured with an outer surface which is flush with the surroundingsurface of the third portion 392 v.

FIG. 106 illustrates a cross-sectional perspective view of a portion ofthe system 104 v, with the safety mechanism 750 in a lockedconfiguration and the first spring 402 v unenergized. The safetymechanism 750 includes a proximally-extending locking tab 752 of thesecond portion and an inwardly-extending overhang (or undercut) 754 ofthe third portion 392 v. In the locked configuration illustrated in FIG.106 , the tab 752 is flexed radially outward and its proximal end isconstrained by the overhang 754, preventing distal movement of the thirdportion 392 v with respect to the second portion 152 v and thuspreventing energization of the spring 392 v. The release button 760includes a protrusion 758 which extends inwardly, in radial alignmentwith a portion of the tab 752. A lateral (e.g. radially inward) forceapplied to the release button 760 pushes the tab 752 radially inward,sliding the proximal end of the tab 752 against an angled surface 756 ofthe overhang 754 and out of engagement with the overhang 754, so thatthe tab 752 can release to an unstressed configuration as shown in FIG.108 . Once the tab 752 is released, the third portion 392 v can be moveddistally with respect to the second portion 152 v, for example toenergize the first spring 402 v. In some embodiments, as illustrated inFIG. 109 , the tab 752 can be configured to prevent further distalmovement of the third portion 392 v beyond a desired threshold, forexample by abutting a distally-facing surface 762 of the third portion392 v.

Although the safety lock mechanism 750 is illustrated in the context ofa system configured to be energized by a user, in some embodiments, apre-energized system can also employ a safety lock mechanism, forexample to prevent premature triggering or activation of an alreadyenergized spring.

In some embodiments, the locking and unlocking (and/or coupling anddecoupling) of the components of a sensor inserter assembly can followthis order: The sensor inserter assembly begins in a resting state inwhich the third portion 392 is locked with respect to the first portion150, the first portion 150 is locked with respect to the second portion152, and the sensor module 134 is coupled to the first portion 150(optionally via the needle hub 162). Before energizing or triggering ofthe insertion spring 402, the third portion 392 is unlocked with respectto the first portion 150 and/or the second portion 150. The insertionspring 402, if not already energized, is then energized by distalmovement of the third portion 392. Then, the third portion 392 is lockedwith respect to the second portion 152. The first portion 150 is thenreleased from the second portion 152 to activate the insertion spring402. As the insertion spring 402 deploys, the sensor module 134 couplesto the base 128. Then the first portion 150 (and/or the needle hub 162)releases the sensor module 134, and the second portion 152 releases thebase 128. In several embodiments, the locations of the various lockingand unlocking (and/or coupling and decoupling) structures along the axisof the assembly are optimized to ensure this order is the only orderthat is possible. (Some embodiments use different locking and unlockingorders of operation.)

Systems such as those illustrated in FIGS. 92-109 provide reliabletrigger mechanisms to release an insertion spring when the insertionspring is in a loaded condition. It is contemplated such systems provideseveral advantages to the user including ease in firing, single handedfiring (by allowing the user to hold onto the sides of the insertiondevice and fire the insertion device using the same hand). It iscontemplated that a system comprising a top trigger can provide asmaller width profile than a system having a side button while requiringless user dexterity.

Release after Deployment

In several embodiments, a sensor inserter system is configured to movean on-skin component (such as, for example, a sensor module 134, asensor assembly (for example comprising a sensor, electrical contacts,and optionally a sealing structure), a combination sensor module andbase, an integrated sensor module and transmitter, an integrated sensormodule and transmitter and base, or any other component or combinationof components which is desirably attached to the skin of a host) from aproximal starting position within the sensor inserter system to a distaldeployed position in which it can attach to the skin of a host, while atthe same time inserting a sensor (which may form part of the on-skincomponent) into the skin of the host. In some embodiments, the sensor iscoupled to electrical contacts of the on-skin component during thedeployment and/or insertion process. In other embodiments, the on-skincomponent is pre-connected, that is to say, the sensor is coupled toelectrical contacts of the on-skin component before the deploymentand/or insertion processes begin. The sensor assembly can bepre-connected, for example, during manufacture or assembly of thesystem.

Thus, in several embodiments, a sensor inserter system can be configuredto releasably secure the on-skin component in its proximal startingposition, at least before or until deployment of the inserter system,and can also be configured to release the on-skin component in a distalposition after the inserter system is deployed. In some embodiments, thesystem can be configured to couple the on-skin component to a baseand/or to an adhesive patch during the deployment process, either as theon-skin component is moved from the proximal starting position to thedistal deployed position or once it reaches the distal deployedposition. In some embodiments, the system can be configured to separatefrom (or become separable from) the on-skin component, base, and/oradhesive patch after the on-skin component is deployed in the distalposition and the needle hub (if any) is retracted.

In embodiments, various mechanical interlocks (e.g., snap fits, frictionfits, interference features, elastomeric grips) and/or adhesives can beused to couple the on-skin component to the sensor inserter system andreleasably secure it in a proximal starting position, and/or to couplethe on-skin component (and base, if any) to the adhesive patch once theon-skin component is deployed. In addition, various mechanical features(e.g. snap fits, friction fits, interference features, elastomericgrips, pushers, stripper plates, frangible members) and/or adhesives canbe used to decouple the on-skin component from the sensor insertersystem once it reaches the distal deployed position. Further, variousmechanical features, (e.g. snap fits, friction fits, interferencefeatures, elastomeric grips, pushers, stripper plates, frangiblemembers) and/or adhesives can be used to separate, unlock, or otherwiserender separable the on-skin component, base, and/or adhesive patch fromthe remainder of the system after the on-skin component is deployed inthe distal position and the needle hub (if any) is retracted.

With reference now to FIGS. 110-119 , a sensor inserter system 104 waccording to some embodiments is illustrated. The system 104 w can beconfigured substantially similar to the system 104 v illustrated withinthe context of FIGS. 105-109 and system 104 m illustrated within thecontext of FIGS. 71-75 , with like reference numerals indicating likeparts. The system 104 w includes, for example, a telescoping assembly132 w including a first portion 150 w, a second portion 152 w, and athird portion 392 w; a safety mechanism 750, a needle hub 162 w; a firstspring 402 w; a second spring 234 w; an on-skin component 134 w, and abase 128 w.

FIG. 110 illustrates a cross-sectional perspective view of the system104 w in a resting and locked state, with the on-skin component 134 wsecured in a proximal starting position. In this state, as well as inthe unlocked state illustrated in FIG. 111 and the energized stateillustrated in FIG. 112 , the on-skin component 134 w is secured in theproximal starting position by a securement member 800. As can be seen inFIG. 110 , the system 104 w includes a secondary locking feature 409 w,configured as a ledge extending from the distal end of the lockingprotrusion 408 w, which is configured to cooperate with an opening 410 wto prevent the third portion 392 from moving in a proximal directionwith respect to the second portion 152 w prior to deployment. In theembodiment illustrated in FIGS. 110-119 , the securement member 800 isintegrally formed with the needle hub 162 w. In other embodiments, thesecurement member can be integrally formed with the first portion 150 w.In still other embodiments, the securement member can be separatelyformed from and operatively coupled to the needle hub 162 w and/or tothe first portion 150 w. The securement member 800 extends substantiallyparallel to the needle 158. In the embodiment illustrated in FIGS.110-119 , the securement member 800 comprises a pair ofdistally-extending legs 802 (see FIGS. 115 and 116 ). Some embodimentscan, however, include only one distally-extending leg 802, while otherscan include three, four, or more legs 802. In embodiments comprisingonly one leg 802, the leg can be configured to adhere or otherwisecouple to a center region or a perimeter of the on-skin component. Inembodiments comprising more than one leg 802, the legs can be configuredto adhere or otherwise couple to the on-skin component symmetrically orasymmetrically about a center of the on-skin component. The legs 802 canhave an ovoid cross section, or can have any other suitable crosssection, including circular, square, triangular, curvilinear, L-shaped,O-shaped, U-shaped, V-shaped, X-shaped, or any other regular orirregular shape or combination of shapes. In embodiments, the securementmember 800 can comprise legs, columns, protrusions, and/or elongatemembers, or can have any other suitable configuration for holding theon-skin component in the proximal starting position.

FIG. 113 illustrates a cross-sectional perspective view of the system104 w, in an activated state, with the insertion spring 402 w activated,the retraction spring 234 w energized, and the needle hub 162 w and thesecurement member 800 moved to a distal deployed position. The on-skincomponent 134 w, being coupled to the securement member 800 until thisstage, has also been moved to a distal deployed position. When theon-skin component 134 w reaches the distal deployed position, it iscoupled to the base 128 w.

FIG. 114 illustrates a cross-sectional perspective view of the system104 w after the on-skin component has been coupled to the base 128 w andthe needle hub 162 w (along with the securement member 800) has beenretracted to a proximal position. After the on-skin component 134 w iscoupled to the base 128 w, a resistance member 804 facilitatesdecoupling of the on-skin component 134 w from the securement member 800by resisting unwanted proximal movement of the on-skin component 134 waway from the base 128 w. Generally, the resistance member 804 can be abackstop or backing structure configured to inhibit or prevent, orotherwise resist any tendency of the on-skin component 134 w to move ina proximal direction as the securement member 800, which is releasablycoupled to the on-skin component 134 w, moves in a proximal direction.Because the first portion 150 w is fixed to the second portion 152 w atthis stage, and the needle hub 162 w is released from the first portion150 w, the needle hub 162 w can retract in a proximal direction whilethe first portion 150 w (and the resistance member 804) remains plantedin a distal position, inhibiting proximal movement of the on-skincomponent 134 w. The energy stored in the retraction spring 234 w issufficient to overcome a retention force and decouple the on-skincomponent 134 w from the securement member 800 and urge the needle hub162 in a proximal direction. The potential energy stored can be between0.25 pounds to 4 pounds. In preferred embodiments, the potential energystored is between about 1 to 2 pounds.

In some embodiments, a sensor inserter system can be configured suchthat the on-skin component couples with the base at approximately thesame time the retraction mechanism is activated. In some embodiments, asensor inserter system can be configured such that the on-skin componentcouples with the base before the retraction mechanism is activated,before the second spring is activated, or otherwise before the secondspring begins retracting the needle hub in a proximal direction awayfrom the deployed position. In some embodiments, a sensor insertersystem can be configured such that the second spring is activated atleast 0.05 seconds, at least 0.1 seconds, at least 0.2 seconds, at least0.3 seconds, at least 0.4 seconds, at least 0.5 seconds, at least 0.6seconds, at least 0.7 seconds, at least 0.8 seconds, at least 0.8seconds, at least 1 second, or longer than 1 second after the on-skincomponent couples with the base. In other embodiments, a sensor insertersystem can be configured such that the second spring is activated atmost 0.05 seconds, at most 0.1 seconds, at most 0.2 seconds, at most 0.3seconds, at most 0.4 seconds, at most 0.5 seconds, at most 0.6 seconds,at most 0.7 seconds, at most 0.8 seconds, at most 0.8 seconds, or atmost 1 second after the on-skin component couples with the base.

The on-skin component 134 w is now coupled with the base 128 w. The base128 w (and adhesive patch) is initially coupled to the second portion152 w by a latch or flex arm 220 w coupled to an undercut or lockingfeature 230 w (similarly shown in FIGS. 18-19 ). When the first portion150 w reaches its most distal position during insertion of the sensor138, a delatching feature of the first portion 150 w pushes the latch ofthe second portion 152 w out of the undercut. This decouples the base128 w from the second portion 152 w, and thus allows the user to takethe remainder of the system 104 w off the skin, leaving only theadhesive patch, the base 128 w, and the on-skin component 134 w on theskin.

In the embodiment illustrated in FIGS. 110-119 , the resistance member804 is integrally formed with the first portion 150 w. In otherembodiments, the resistance member can be integrally formed with thesecond portion 152 w. In still other embodiments, the resistance membercan be separately formed from and operatively coupled to the firstportion 150 w and/or to the second portion 152 w. In the embodimentillustrated in FIGS. 110-119 , the resistance member 804 comprises adistally-facing surface of the first portion 150 w.

The system 104 w can be configured to couple the on-skin component 134 wto the base 128 w via an adhesive 806. FIG. 115 illustrates aperspective view of the needle hub 162 w, shown securing the on-skincomponent 134 w during deployment, with the base 128 w removed toillustrate the adhesive 806 disposed on a distally-facing surface of theon-skin component 134 w. The adhesive 806 can be configured to couplethe on-skin component 134 w to the base 128 w on contact. Alternativelyor in addition to the adhesive 806, some embodiments can include anadhesive disposed on a proximally-facing surface of the base, so as tocouple the on-skin component to the base upon contact. In someembodiments, the adhesive can be a pressure-sensitive adhesive. In someembodiments, the securement member can be configured to couple theon-skin component to the needle hub only along a plane extending normalto the axial direction of the system. In addition or in the alternative,the securement can be configured to couple the on-skin component in alateral or radial direction.

FIG. 116 illustrates another perspective view of the needle hub 162 w,shown decoupled from the on-skin component 134 w, with the base 128 wremoved to illustrate the adhesive 808 disposed on the distally-facingsurfaces of the securement member 800. The adhesive 808 can beconfigured to couple the on-skin component 134 w to the securementmember 800 while in the proximal starting position and during movementof the on-skin component 134 w in the proximal direction, and to allowthe release of the on-skin component 134 w from the securement member800 after the on-skin component 134 w is coupled to the base 128 w.Alternatively or in addition to the adhesive 808, some embodiments caninclude an adhesive disposed on a proximally-facing surface of theon-skin component 134 w. In some embodiments, the adhesive can be apressure-sensitive adhesive. In some embodiments, the adhesive 808 canhave a smaller surface area and/or a lower adhesion strength than theadhesive 806, such that the adhesion strength of the adhesive 806 whichcouples the on-skin component to the base outweighs the adhesionstrength of the adhesive 808 which couples the on-skin component to thesecurement member. In other embodiments, the adhesion strength of theadhesive 808 can be the same or greater than the adhesion strength ofthe adhesive 806. In these embodiments, a resistance member can beemployed to facilitate the decoupling of the on-skin component 134 wfrom the securement member 800 after deployment.

FIG. 117 illustrates a perspective view of a portion of the system 104w, illustrating the resistance member 804. The resistance member 804 isconfigured to rest above and/or contact a proximally-facing surface ofthe on-skin component 134 w, at least when the on-skin component 134 wis in a distal deployed position. The resistance member 804 can serve toinhibit proximal movement of the on-skin component 134 w as the needlehub 162 w and securement member 800 retract in a proximal direction. Theresistance member 804 can function in a manner similar to a stripperplate in punch and die manufacturing or injection molding processes.

In embodiments, the resistance member can have any configurationsuitable for resisting decoupling of the on-skin component from thebase. In the embodiment illustrated in FIGS. 110-119 , the resistancemember 804 has a curvilinear cross section, and extends through an arcof roughly 300 degrees about the perimeter of the on-skin component 134w. In some embodiments, the resistance member 804 can extend through anarc of roughly 30 degrees, 60 degrees, 90 degrees, 120 degrees, 150degrees, 180 degrees, 210 degrees, 240 degrees, 270 degrees, 300degrees, or 330 degrees about the perimeter of the on-skin component 134w, or through an arc greater than, less than, or within a range definedby any of these numbers. In some embodiments, the resistance member 804can extend continuously or discontinuously about the perimeter of theon-skin component. In some embodiments, the resistance member 804 canextend about the entire perimeter of the on-skin component. In someembodiments, the resistance member 804 can comprise one or more contactpoints or surfaces that hold the on-skin component 134 w in the distalposition as the securement feature 800 moves in an opposite (e.g.,proximal) direction.

In other embodiments, the resistance member 804 can comprise multiplediscrete members (e.g., legs) configured to contact multiple locationsabout the perimeter of the on-skin component 134 w. For example, in someembodiments, the resistance member 804 can include at least two legsdisposed apart from one another about a center point of the on-skincomponent. In some embodiments, the resistance member 804 can includetwo legs disposed roughly 180 degrees about a center point of theon-skin component. In some embodiments, the resistance member 804 caninclude three legs disposed roughly 120 degrees about a center point ofthe on-skin component. In such an embodiment, the legs can be arrangedsymmetrically about the on-skin component (e.g. with radial symmetry, orreflectional/bilateral symmetry).

FIG. 117 also illustrates locator features 810 which can be formed in,or integrally coupled to, the first portion 150 w and/or the resistancemember 804. The locator features 810 can comprise distally-extendingtabs of the first portion 150 w and/or of the resistance member 804. Thelocator features 810 can be configured to align with correspondingindentations 812 in the on-skin component (see FIG. 119 ) so as toensure proper positioning of the sensor module 134 w with respect to thefirst portion 150 w and/or the resistance member 804 during assembly.

FIG. 118 illustrates a perspective view of the sensor module 134 w,before being coupled to the base 128 w by contacting the adhesive 806.The base 128 w itself is coupled (for example by an adhesive) to aproximal surface of an adhesive patch 900. FIG. 119 illustrates aperspective view of the sensor module 134 w after being coupled to thebase 128 w on the adhesive patch 900.

In embodiments, providing a resistance member can facilitate a reliabletransfer of the on-skin component to the base, by creating acounterforce against the securement member as the needle hub retracts inthe proximal direction. The counterforce allows the securement member toseparate from the on-skin component while inhibiting or preventing thedisengagement of the on-skin component from the base (if any) and/orfrom the adhesive patch. In embodiments, the retraction spring can beconfigured to store and provide sufficient energy to both retract theneedle and decouple the on-skin component from the needle hub. Thecombination of the resistance member and securement member can also beconfigured to provide positional control of the on-skin component from asecured configuration (e.g., in the proximal starting position andduring movement of the on-skin component toward the distal deployedposition) to a released configuration (when the on-skin componentreaches the distal deployed position and/or couples to the base and/oradhesive patch).

It is contemplated that providing a base which begins in the distaldeployed position when the system is in a resting or stored state canserve to protect the needle (and the user) before the system isdeployed. For example, a base which is coupled to a distal end of thesystem in a resting or pre-deployment state can prevent a user fromreaching into the distal end of the system and pricking him or herself.This configuration can thus potentially reduce needle stick hazards. Inaddition, a base which is coupled to a distal end of the system in aresting or pre-deployment state facilitate the setting of the adhesivepatch on the skin before deployment. For example, with such aconfiguration, the user can use the body of the sensor inserter systemto assist in applying a force in a distal direction to adhere theadhesive patch to the skin. In addition, the base can provide structuralsupport to guide the needle into the skin during deployment.

FIGS. 120-122 illustrate another configuration for coupling an on-skincomponent to a base, in accordance with several embodiments. FIG. 120shows a side view of an on-skin component 134 x and a base 128 x, priorto coupling of the on-skin component 134 x to the base 128 x. Theon-skin component 134 x includes a distally-extending sensor 138, andthe base 128 x is coupled to an adhesive patch 900. FIG. 121 illustratesa perspective view of these same components. The base 128 x comprises aflexible elastomeric member with a proximally-extending ridge 814extending about a proximally-facing surface 816. The base 128 x can havea shape configured to correspond to a shape of the on-skin component 134x. In a relaxed state, as illustrated in FIGS. 120 and 121 , and beforemaking contact with the on-skin component 134 x, the base 128 x has adeformed, somewhat convex curvature. The base 128 x and the adhesivepatch 900 can be coupled to the other components of a sensor inserterassembly in this configuration. During deployment, as the on-skincomponent 134 x begins to contact the base 128 x, the proximally-facingsurface 816 flexes up to meet the distal surface of the on-skincomponent 134 x, causing the ridge 814 to grip securely about theperimeter of the on-skin component 134 x, as illustrated in FIG. 122 .

FIG. 123 illustrates a perspective view of a portion of another insertersystem 104 y, according to some embodiments. The system 104 y can beconfigured substantially similar to any of the systems 104 illustratedherein, with like reference numerals indicating like parts. The insertersystem 104 y includes an on-skin component 134 y which includes acombination sensor module and base. In embodiments, the combinationsensor module and base can be integrally formed with one another, asillustrated in FIG. 123 , or operatively coupled to one another. Thesystem 104 y also includes a securement member 800 y which is configuredto releasably secure the on-skin component 134 y in a proximal startingposition, at least until the system 104 y is activated. The securementmember 800 y is integrally formed with the needle hub 162 y, andincludes three proximally-extending legs 802 y configured to releasablycouple to (e.g. via adhesive 808) various locations on the proximalsurface of the on-skin component 134 y. It is contemplated that theaddition of a third (or further) leg 802 y can help to balance thesensor module and prevent it from canting to one side or another duringdeployment and/or retraction. The system 104 y also includes aresistance member 804. The resistance member 804 may be integrallymolded with first portion 150 y.

FIG. 124 illustrates another perspective view of the on-skin component134 y and the needle hub 162 y, with the remainder of the system 104 yremoved to illustrate the configuration of the securement member 800 y.FIG. 125 illustrates a perspective view of a portion of the applicatorsystem shown in FIG. 123 , with the on-skin component 134 y in areleased configuration and separated from the needle hub 162 y and withtwo of the legs 802 y removed for purposes of illustration. Theresistance member 804 y can be configured to encompass or at leastpartially encompass the sensor module portion of the on-skin component134 y. The resistance member 804 y can comprise one or more elongatemembers, columns, legs, and/or protrusions, or can have any othersuitable configuration for facilitating the release of the on-skincomponent from the needle hub 162 y. The resistance member 804 y (or anyportion thereof) can have a curvilinear cross section, as illustrated inFIG. 125 , or can have any other suitable cross section, includingcircular, square, triangular, ovoid, L-shaped, O-shaped, U-shaped,V-shaped, X-shaped, or any other regular or irregular shape orcombination of shapes.

As shown in FIG. 125 , the system 104 y can include an adhesive patch818 disposed on the distally-facing surface of the on-skin component 134y. The adhesive patch 818 can be configured to couple the on-skincomponent 134 y to the skin on contact. In some embodiments, theadhesive patch can be a pressure-sensitive adhesive. In someembodiments, the adhesive patch 818 is a double sided adhesive, in whichan adhesive is disposed on both the proximally facing surface of theadhesive patch 818 and the distally facing surface of the adhesive patch818. The proximally facing adhesive can be configured to couple with thedistal end of the on-skin component 134 y, and the distally facingadhesive can be configured to couple with the skin. In otherembodiments, the proximally facing surface of the adhesive patch 818 isconfigured to couple with the distally facing surface of the on-skincomponent by a coupling process such as, but not limited to, heatstaking, fastening, welding, or bonding. In some embodiments, theadhesive patch 818 can be covered by a removable liner prior todeployment. In other embodiments, the adhesive patch 818 can be exposed(e.g., uncovered) within the system prior to deployment.

Alternatively, in some embodiments the adhesive patch 818 can bereleasably secured to the distal end of the system before deployment,with an adhesive disposed on a proximally-facing surface of the adhesivepatch 818, so as to couple the on-skin component to the adhesive patch818 upon contact as part of the sensor insertion process. In addition,in such an embodiment, the adhesive patch 818 can include an adhesivedisposed on a distally-facing surface of the adhesive patch 818 tocouple the on-skin component to the skin.

Such a configuration can include fewer components to be coupled anddecoupled during the deployment and insertion process, which canincrease reliability of systems configured in accordance withembodiments. For example, systems configured in accordance withembodiments can reduce the chance of improper transfer of systemcomponents to the skin. In addition, it is contemplated that embodimentscomprising an adhesive patch disposed within the system in a restingstate (as opposed to an adhesive patch disposed at a distal end of thesystem in the resting state) can allow for the system to be more easilyre-positioned on the skin as many times as desired before being adheredto the skin.

FIGS. 126-128 illustrate another configuration for releasably securingan on-skin component in a proximal position, in accordance with severalembodiments. FIG. 126 illustrates a perspective view of a portion of asecurement member 800 z shown secured to an on-skin component 134 zcomprising a sensor module. The securement member 800 z can include atleast one leg 802 z. As shown in the figure, the securement member 800 zincludes two proximally-extending legs 802 z. The on-skin component 134z includes two elastomeric grips 824 extending laterally from the sensormodule. The grips 824 are sized and shaped to cooperate withlaterally-facing surfaces of the legs 802 z to releasably secure theon-skin component 134 z in a proximal position. In the embodimentillustrated in FIGS. 126-128 , the grips 824 are integrally formed withthe sensor module, and have a bracket-shaped cross section, as viewed ina plane extending normal to the axial direction. In embodiments, thesecurement member 800 z and the grips 824 can have any suitablecooperating configuration to allow the on-skin component 134 z toreleasably couple the securement member 800 z to the grips 824, forexample via a friction fit, interference fit, or corresponding undercutengagement features. Some embodiments can additionally employ anadhesive disposed between the securement member 800 z and the on-skincomponent 134 z, to provide additional securement of the on-skincomponent 134 z.

FIG. 127 illustrates a perspective view of a portion of the securementmember 800 z, with the sensor module of the on-skin component 134 zshown in cross section to illustrate the configuration of the grips 824.FIG. 127 also shows a decoupling feature 804 z configured to resistproximal movement of the on-skin component 134 z after deployment of theon-skin component 134 z to the distal deployed position, for exampleduring retraction of the needle hub 162 z. The decoupling feature 804 zcan be fixed with respect to the remainder of the sensor inserter systemas the needle hub 162 z retracts in a proximal direction, providingenough resistance to overcome the friction fit (and adhesive, if any)between the securement member 800 z and the grips 824 to release thesecurement member 800 z from the grips 824. FIG. 128 illustrates aperspective view of the on-skin component 134 z, after decoupling of theon-skin component 134 z from the securing member 800 z.

FIGS. 129-131 illustrate still another configuration for releasablysecuring an on-skin component, in accordance with several embodiments.FIG. 129 illustrates a perspective view of a portion of a sensorinserter assembly 104 aa with the second portion 150 aa shown in crosssection, and with a securing member 800 aa shown securing an on-skincomponent 134 aa in a proximal position. The on-skin component 134 aamay comprise an integrally formed sensor module/base assembly. As shownin the figure, the securement member 800 aa comprises an elastomeric capwhich is coupled to a portion of the on-skin component 134 aa. As shown,the securement member 800 aa can be coupled to a protrusion (or neck)826 formed in the on-skin component 134 aa. FIG. 130 illustrates aperspective view of a portion of the assembly 104 aa of FIG. 129 , shownwith a portion of the securing member 800 aa cut away to betterillustrate the configuration of the securing member 800 aa and theprotrusion 826. The protrusion 826 can be configured to encircle, or atleast partially encircle, the needle 158 when it extends in a proximaldirection through the on-skin component 134 aa. The protrusion 826 canalso be configured to secure the securement member 800 aa to the on-skincomponent 134 aa. The securement member 800 aa has an opening 828 whichis sized and shaped to create a friction fit between the opening 828 andthe needle 158. In the configuration illustrated in FIGS. 129 and 130 ,with the needle 158 extending distally through the securement member 800aa and the protrusion 826, the friction fit between the securementmember 800 aa and the needle 158 serves to resist at least distalmovement of the on-skin component 134 aa with respect to the needle 158.

The embodiment illustrated in FIGS. 129-131 may also include aresistance member 804 aa. The resistance member may be substantiallysimilar to any resistance member described in FIGS. 110-128 . Theresistance member 804 aa can include a distally-facing surface of thefirst portion 150 aa, and can have a similar configuration to theresistance member 804 described in the context of FIG. 117 . Theresistance member 804 aa can provide enough resistance in a distaldirection to allow the second spring and needle hub (not shown) toovercome the friction fit between the securement member 800 aa and theneedle 158. It is contemplated that this would allow the needle 158 toretract away from the skin and at the same time allow the needle todecouple from the securement member 800 aa. FIG. 131 illustrates aperspective view of a portion of the assembly 104 aa, after decouplingof the on-skin component 134 aa from the needle 158, shown with theprotrusion 826 of the on-skin component 134 aa and the securing member800 aa cut away for purposes of illustration.

FIGS. 132-133 illustrate another configuration for releasably securingan on-skin component in a proximal position, in accordance with severalembodiments. FIG. 132 illustrates a perspective view of a portion of asecurement member 800 ab shown secured to an on-skin component 134 abcomprising a sensor module, with the second portion 150 ab shown incross section. The securement member 800 ab may include at least oneengagement feature. As shown in the figure, the at least one engagementfeature can be two proximally-extending legs 802 ab. The on-skincomponent 134 ab may include at least one receiving feature. As shown,the at least one receiving feature can be two elastomeric grips 824 abextending laterally from the on-skin component 134 ab. The grips 824 abare deformable and sized and shaped to receive the legs 802 ab viafriction or interference fit and thereby releasably secure the on-skincomponent 134 ab in a proximal position. In the embodiment illustratedin FIGS. 132-133 , the legs 802 ab of the securement member 800 ab havea circular cross-section. The grips 824 ab are integrally formed withthe sensor module, and have an annular-shaped cross section, as viewedin a plane extending normal to the axial direction. The grips 824 ab mayeach include an opening which can be configured to receive the legs 802ab via frictional engagement. In embodiments, the securement member 800ab and the grips 824 ab can have any suitable cooperating configurationto releasably couple the securement member 800 ab to the grips 824 ab.Some embodiments can additionally employ an adhesive disposed axiallybetween the securement member 800 ab and the on-skin component 134 ab,to provide additional securement of the on-skin component 134 ab in theproximal starting position. FIG. 133 illustrates a perspective view ofthe needle hub 162 ab and the on-skin component 134 ab, after decouplingof the on-skin component 134 ab from the needle hub 162 ab.

FIGS. 134-136 illustrate yet another configuration for releasablysecuring an on-skin component in a proximal position. FIG. 134illustrates an exploded perspective view of a portion of an assembly 134ac, with a securement member 800 ac configured to releasably couple anon-skin component 134 ac to a needle hub 162 ac. The securement member800 ac may include at least one engagement feature. As shown in thefigure, the securement member 800 ac can include twoproximally-extending legs 802 ac. The on-skin component 134 ac includestwo elastomeric grips 824 ac extending laterally from the sensor module.The grips 824 ac are sized and shaped to receive the legs 802 ac in asnap fit to securely hold the on-skin component 134 ac in a proximalposition. In the embodiment illustrated in FIGS. 134-136 , the legs 802ac of the securement member 800 ac have a circular cross-section, with arecessed section 832 configured to receive the grips 824 ac. The grips824 ac can be integrally formed with the sensor module, each grip havinga frangible link 830 coupling the grips 824 ac to the sensor module. Thegrips 824 ac have an annular-shaped cross section, as viewed in a planeextending normal to the axial direction, the grips being configured toreceive the recessed sections 832 of the legs in a secure interlockingengagement. In embodiments, the securement member 800 ab and the grips824 ab can have any suitable cooperating configuration to securelycouple the securement member 800 ac to the grips 824 ac and preventslippage of the grips along the legs 802 ac as the needle hub 162 acdeploys and as it retracts after deployment. Some embodiments canadditionally employ an adhesive disposed axially between the securementmember 800 ac and the on-skin component 134 ab, to provide additionalsecurement of the on-skin component 134 ac in the proximal startingposition and during deployment.

FIG. 135 illustrates a perspective view of a portion of the system 104ac, with the securement member 800 ac securely coupled to the on-skincomponent 134 ac. Some embodiments can additionally employ an adhesivedisposed axially between the securement member 800 ac and the on-skincomponent 134 ac, to provide additional securement of the on-skincomponent 134 ac in the proximal starting position. The frangible links830 are configured to shear or otherwise detach upon application of aminimum threshold of force, as the needle hub 162 retracts in a proximaldirection after deployment, separating the grips 824 ac from theremainder of the on-skin component 134 ac and leaving the on-skincomponent 824 ac in the deployed distal position. FIG. 136 illustrates aperspective view of a portion of the system 104 ac, with the frangiblelinks 830 broken and the securement member 800 ac decoupled from theon-skin component 134 ac. In some embodiments, a resistance member canalso be employed to prevent proximal movement of the on-skin component134 ac as the needle hub 162 ac retracts, facilitating the breakage ofthe frangible links 830.

Frangible couplings can also be employed between an on-skin componentand the second portion of a sensor inserter system to releasably securethe on-skin component in a proximal starting position prior todeployment. For example, FIGS. 137-140 illustrate various perspectiveviews of a sensor inserter system 104 ad with an on-skin component 134ad releasably secured in a proximal position within the system 104 ad.The on-skin component 134 ad can include a combination sensor module andbase disposed on an adhesive patch 900 ad. To facilitate in releasablysecuring the on-skin component 134 ad to the second portion 152 ad, thesecond portion 152 ad can include at least one distally-extendingprotrusion 834. As shown in the figure, the second portion 152 adincludes four distally-extending protrusions 834 configured to securelycouple with corresponding sockets 836 formed in or otherwise extendingfrom the adhesive patch 900 ad. The sockets 836 are connected to theadhesive patch 900 ad via frangible links 838, which can also beintegrally formed in the adhesive patch 900 ad. In the resting stateillustrated in FIG. 137 , the adhesive patch 900 ad is secured in aproximal position by the coupling of the sockets 836 to the posts 838.As the system 104 ad is deployed and a force is applied to the on-skincomponent 134 ad in a distal direction, the frangible links 838 detach,allowing the adhesive patch 900 ad (and the on-skin component 134 adwhich is already coupled thereto) to move to the distal deployedposition. FIG. 138 illustrates a perspective view of the sensor insertersystem 104 ad, with the frangible links 838 detached and the adhesivepatch 900 ad released from securement. FIGS. 139 and 140 illustrateperspective views of the adhesive patch 900 ad and the on-skin component134 ad, with the frangible links 838 in intact and detachedconfigurations, respectively. Once the frangible links 838 are detachedand the on-skin component 134 ad (along with the patch 900 ad) isdeployed in the distal position, the remainder of the system 104 ad caneasily be lifted off the skin of the host and removed.

FIG. 141 illustrates another configuration for releasably securing abase and adhesive patch to a sensor inserter assembly. FIG. 141illustrates a cross-sectional perspective view of a portion of a system104 ae, with the first portion 150 ae, the second portion 152 ae, andthe third portion 392 ae shown in cross section. The system 104 aeincludes an on-skin component 134 ae which is releasably secured in aproximal starting position. The system 104 ae also includes a base 128ae coupled to an adhesive patch 900 ae. The base 128 ae and the adhesivepatch 900 ae are disposed in a distal position, at a distal end of thesystem 104 ae. The base 128 ae is coupled to the system 104 ae via aplurality of ribs 840 extending radially inward from the second portion152 ae. The ribs 840 can be sized and shaped to grip the edges of thebase 128 ae with a friction/interference fit. The friction/interferencefit between the ribs 840 and the base 128 ae can be configured to bestrong enough to securely couple the base 128 ae to the system 104 aeduring storage and prior to deployment, but weak enough that theadhesive coupling between the adhesive patch 900 ae and the skin of thehost overcomes the strength of the friction fit. Thus, once the adhesivepatch 900 ae is adhered to the skin of the host, the second portion 152ae can be lifted off the base 128 ae and the sensor system 104 ae can beremoved without pulling the base 128 in a proximal direction. In someembodiments, the base 128 ae may comprise an elastomeric material.Further, in some embodiments, the base 128 ae may have a hardness valueless than a hardness value of the on-skin component 134 ae. In otherembodiments, the base 128 ae may have a hardness value more than ahardness value of the on-skin component 134 ae.

FIGS. 142 and 143 illustrate yet another configuration for releasablysecuring an adhesive patch, optionally including a base, to a sensorinserter system. FIG. 142 shows a sensor inserter system 104 af with anadhesive patch 900 af coupled to the second portion 152 af of the system104 af. FIG. 143 shows the system 104 af with the patch 900 af separatedfrom the second portion 152 af. As shown in FIG. 143 , the secondportion 152 af includes a plurality of adhesive dots 842 disposed on adistally-facing surface or edge of the second portion 152 af. Theadhesive dots 842 can be configured to be strong enough to securelycouple the adhesive patch 900 af (and base, if any) to the system 104 afduring storage and prior to deployment, but weak enough that theadhesive coupling between the adhesive patch 900 af and the skin of thehost overcomes the strength of the adhesive dots 842. Thus, once theadhesive patch 900 af is adhered to the skin of the host, the secondportion 152 af can be lifted off the applicator patch 900 af (and base,if any) and the sensor system 104 af can be removed without pulling theadhesive patch 900 af (or base, if any) in a proximal direction.Alternatively or in addition to the adhesive dots 842, some embodimentscan include an adhesive disposed on a proximally-facing surface of theadhesive patch 900 af. In some embodiments, the adhesive can be apressure-sensitive adhesive.

Interpretation

For ease of explanation and illustration, in some instances the detaileddescription describes exemplary systems and methods in terms of acontinuous glucose monitoring environment; however it should beunderstood that the scope of the invention is not limited to thatparticular environment, and that one skilled in the art will appreciatethat the systems and methods described herein can be embodied in variousforms. Accordingly any structural and/or functional details disclosedherein are not to be interpreted as limiting the systems and methods,but rather are provided as attributes of a representative embodimentand/or arrangement for teaching one skilled in the art one or more waysto implement the systems and methods, which may be advantageous in othercontexts.

For example, and without limitation, described monitoring systems andmethods may include sensors that measure the concentration of one ormore analytes (for instance glucose, lactate, potassium, pH,cholesterol, isoprene, and/or hemoglobin) and/or other blood or bodilyfluid constituents of or relevant to a host and/or another party.

By way of example, and without limitation, monitoring system and methodembodiments described herein may include finger-stick blood sampling,blood analyte test strips, non-invasive sensors, wearable monitors (e.g.smart bracelets, smart watches, smart rings, smart necklaces orpendants, workout monitors, fitness monitors, health and/or medicalmonitors, clip-on monitors, and the like), adhesive sensors, smarttextiles and/or clothing incorporating sensors, shoe inserts and/orinsoles that include sensors, transdermal (i.e. transcutaneous) sensors,and/or swallowed, inhaled or implantable sensors.

In some embodiments, and without limitation, monitoring systems andmethods may comprise other sensors instead of or in additional to thesensors described herein, such as inertial measurement units includingaccelerometers, gyroscopes, magnetometers and/or barometers; motion,altitude, position, and/or location sensors; biometric sensors; opticalsensors including for instance optical heart rate monitors,photoplethysmogram (PPG)/pulse oximeters, fluorescence monitors, andcameras; wearable electrodes; electrocardiogram (EKG or ECG),electroencephalography (EEG), and/or electromyography (EMG) sensors;chemical sensors; flexible sensors for instance for measuring stretch,displacement, pressure, weight, or impact; galvanometric sensors,capacitive sensors, electric field sensors, temperature/thermal sensors,microphones, vibration sensors, ultrasound sensors,piezoelectric/piezoresistive sensors, and/or transducers for measuringinformation of or relevant to a host and/or another party.

None of the steps described herein is essential or indispensable. Any ofthe steps can be adjusted or modified. Other or additional steps can beused. Any portion of any of the steps, processes, structures, and/ordevices disclosed or illustrated in one embodiment, flowchart, orexample in this specification can be combined or used with or instead ofany other portion of any of the steps, processes, structures, and/ordevices disclosed or illustrated in a different embodiment, flowchart,or example. The embodiments and examples provided herein are notintended to be discrete and separate from each other.

The section headings and subheadings provided herein are nonlimiting.The section headings and subheadings do not represent or limit the fullscope of the embodiments described in the sections to which the headingsand subheadings pertain. For example, a section titled “Topic 1” mayinclude embodiments that do not pertain to Topic 1 and embodimentsdescribed in other sections may apply to and be combined withembodiments described within the “Topic 1” section.

Some of the devices, systems, embodiments, and processes use computers.Each of the routines, processes, methods, and algorithms described inthe preceding sections may be embodied in, and fully or partiallyautomated by, code modules executed by one or more computers, computerprocessors, or machines configured to execute computer instructions. Thecode modules may be stored on any type of non-transitorycomputer-readable storage medium or tangible computer storage device,such as hard drives, solid state memory, flash memory, optical disc,and/or the like. The processes and algorithms may be implementedpartially or wholly in application-specific circuitry. The results ofthe disclosed processes and process steps may be stored, persistently orotherwise, in any type of non-transitory computer storage such as, forexample, volatile or non-volatile storage.

Any of the features of each embodiment is applicable to all aspects andembodiments identified herein. Moreover, any of the features of anembodiment is independently combinable, partly or wholly with otherembodiments described herein in any way, e.g., one, two, or three ormore embodiments may be combinable in whole or in part. Further, any ofthe features of an embodiment may be made optional to other aspects orembodiments. Any aspect or embodiment of a method can be performed by asystem or apparatus of another aspect or embodiment, and any aspect orembodiment of a system can be configured to perform a method of anotheraspect or embodiment.

The various features and processes described above may be usedindependently of one another, or may be combined in various ways. Allpossible combinations and subcombinations are intended to fall withinthe scope of this disclosure. In addition, certain method, event, state,or process blocks may be omitted in some implementations. The methods,steps, and processes described herein are also not limited to anyparticular sequence, and the blocks, steps, or states relating theretocan be performed in other sequences that are appropriate. For example,described tasks or events may be performed in an order other than theorder specifically disclosed. Multiple steps may be combined in a singleblock or state. The example tasks or events may be performed in serial,in parallel, or in some other manner. Tasks or events may be added to orremoved from the disclosed example embodiments. The example systems andcomponents described herein may be configured differently thandescribed. For example, elements may be added to, removed from, orrearranged compared to the disclosed example embodiments.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orsteps. Thus, such conditional language is not generally intended toimply that features, elements and/or steps are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or steps are included or are to beperformed in any particular embodiment. The terms “comprising,”“including,” “having,” and the like are synonymous and are usedinclusively, in an open-ended fashion, and do not exclude additionalelements, features, acts, operations and so forth. Also, the term “or”is used in its inclusive sense (and not in its exclusive sense) so thatwhen used, for example, to connect a list of elements, the term “or”means one, some, or all of the elements in the list. Conjunctivelanguage such as the phrase “at least one of X, Y, and Z,” unlessspecifically stated otherwise, is otherwise understood with the contextas used in general to convey that an item, term, etc. may be either X,Y, or Z. Thus, such conjunctive language is not generally intended toimply that certain embodiments require at least one of X, at least oneof Y, and at least one of Z to be present.

The term “and/or” means that “and” applies to some embodiments and “or”applies to some embodiments. Thus, A, B, and/or C can be replaced withA, B, and C written in one sentence and A, B, or C written in anothersentence. A, B, and/or C means that some embodiments can include A andB, some embodiments can include A and C, some embodiments can include Band C, some embodiments can only include A, some embodiments can includeonly B, some embodiments can include only C, and some embodiments caninclude A, B, and C. The term “and/or” is used to avoid unnecessaryredundancy.

All references cited herein are incorporated herein by reference intheir entirety. To the extent publications and patents or patentapplications incorporated by reference contradict the disclosurecontained in the specification, the specification is intended tosupersede and/or take precedence over any such contradictory material.

Unless otherwise defined, all terms (including technical and scientificterms) are to be given their ordinary and customary meaning to a personof ordinary skill in the art, and are not to be limited to a special orcustomized meaning unless expressly so defined herein. It should benoted that the use of particular terminology when describing certainfeatures or aspects of the disclosure should not be taken to imply thatthe terminology is being re-defined herein to be restricted to includeany specific characteristics of the features or aspects of thedisclosure with which that terminology is associated. Terms and phrasesused in this application, and variations thereof, especially in theappended claims, unless otherwise expressly stated, should be construedas open ended as opposed to limiting.

While certain example embodiments have been described, these embodimentshave been presented by way of example only, and are not intended tolimit the scope of the inventions disclosed herein. Thus, nothing in theforegoing description is intended to imply that any particular feature,characteristic, step, module, or block is necessary or indispensable.Indeed, the novel methods and systems described herein may be embodiedin a variety of other forms; furthermore, various omissions,substitutions, and changes in the form of the methods and systemsdescribed herein may be made without departing from the spirit of theinventions disclosed herein.

What is claimed is:
 1. A transcutaneous analyte sensor system comprising: a transcutaneous analyte sensor; and sensor electronics operably connectable to the transcutaneous analyte sensor. 